Rule2024-31142
Federal Motor Vehicle Safety Standards; Child Restraint Systems, Child Restraint Anchorage Systems, Incorporation by Reference
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
January 7, 2025
Effective
March 10, 2025
Issuing agencies
Transportation DepartmentNational Highway Traffic Safety Administration
Abstract
This final rule amends Federal Motor Vehicle Safety Standard (FMVSS) No. 225; Child restraint systems, and FMVSS No. 213b; Child restraint systems, to improve ease-of-use of the lower and tether anchorages, improve correct use of child restraint systems in vehicles, and maintain or improve the correct use and effectiveness of child restraint systems (CRSs) in motor vehicles. This final rule fulfills a mandate of the Moving Ahead for Progress in the 21st Century Act (MAP- 21) requiring that NHTSA improve the ease-of-use for lower anchorages and tethers in all rear seat positions.
Full Text
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<title>Federal Register, Volume 90 Issue 4 (Tuesday, January 7, 2025)</title>
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[Federal Register Volume 90, Number 4 (Tuesday, January 7, 2025)]
[Rules and Regulations]
[Pages 1288-1353]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-31142]
[[Page 1287]]
Vol. 90
Tuesday,
No. 4
January 7, 2025
Part III
Department of Transportation
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National Highway Traffic Safety Administration
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49 CFR Parts 571 and 585
Federal Motor Vehicle Safety Standards; Child Restraint Systems, Child
Restraint Anchorage Systems, Incorporation by Reference; Final Rule
Federal Register / Vol. 90 , No. 4 / Tuesday, January 7, 2025 / Rules
and Regulations
[[Page 1288]]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Parts 571 and 585
[Docket No. NHTSA-2024-0089]
RIN 2127-AL20
Federal Motor Vehicle Safety Standards; Child Restraint Systems,
Child Restraint Anchorage Systems, Incorporation by Reference
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation (DOT).
ACTION: Final rule.
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SUMMARY: This final rule amends Federal Motor Vehicle Safety Standard
(FMVSS) No. 225; Child restraint systems, and FMVSS No. 213b; Child
restraint systems, to improve ease-of-use of the lower and tether
anchorages, improve correct use of child restraint systems in vehicles,
and maintain or improve the correct use and effectiveness of child
restraint systems (CRSs) in motor vehicles. This final rule fulfills a
mandate of the Moving Ahead for Progress in the 21st Century Act (MAP-
21) requiring that NHTSA improve the ease-of-use for lower anchorages
and tethers in all rear seat positions.
DATES:
Effective date: March 10, 2025.
IBR date: The incorporation by reference of certain publications
listed in the rule is approved by the Director of the Federal Register
beginning March 10, 2025.
Compliance date: This final rule adopts a 3-year phase-in period to
comply with the updated requirements in FMVSS No. 225. The phase-in
begins on September 1, 2028, and requires that 20 percent of a
manufacturer's applicable vehicles produced from September 1, 2028, to
August 31, 2029, comply with the updated FMVSS No. 225, followed by 50
percent from September 1, 2029, to August 31, 2030, and 100 percent on
and after September 1, 2030. Early compliance is permitted.
Reconsideration date: If you wish to petition for reconsideration
of this rule, your petition must be received by February 21, 2025.
ADDRESSES: Petitions for reconsideration of this final rule must refer
to the docket number set forth above and be submitted to the
Administrator, National Highway Traffic Safety Administration, 1200 New
Jersey Avenue SE, Washington, DC 20590. Note that all petitions
received will be posted without change to <a href="http://www.regulations.gov">www.regulations.gov</a>,
including any personal information provided.
Confidential Business Information: If you wish to submit any
information under a claim of confidentiality, you should submit your
complete submission, including the information you claim to be
confidential business information, to the Chief Counsel, NHTSA, at the
address given under FOR FURTHER INFORMATION CONTACT. In addition, you
should submit a copy, from which you have deleted the claimed
confidential business information, to Docket Management at the address
given above. When you send a submission containing information claimed
to be confidential business information, you should include a cover
letter setting forth the information specified in our confidential
business information regulation (49 CFR part 512). Please see further
information in the Regulatory Notices and Analyses section of this
preamble.
Privacy Act: The petition will be placed in the docket. Anyone is
able to search the electronic form of all documents received into any
of our dockets by the name of the individual submitting the comment (or
signing the comment, if submitted on behalf of an association,
business, labor union, etc.). You may review DOT's complete Privacy Act
Statement in the Federal Register published on April 11, 2000 (65
FR19477-78) or you may visit <a href="http://www.transportation.gov/individuals/privacy/privacy-act-system-records-notices">www.transportation.gov/individuals/privacy/privacy-act-system-records-notices</a>.
Docket: For access to the docket to read background documents or
comments received, go to <a href="http://www.regulations.gov">www.regulations.gov</a>, or the street address
listed above. Follow the online instructions for accessing the dockets.
FOR FURTHER INFORMATION CONTACT: For technical issues, you may call
Cristina Echemendia, Office of Crashworthiness Standards (phone: 202-
366-6345). For legal issues, you may call Natasha Reed, Office of the
Chief Counsel (phone: 202-366-2992). The mailing address of these
officials is: National Highway Traffic Safety Administration, U.S.
Department of Transportation, 1200 New Jersey Avenue SE, West Building,
Washington, DC 20590.
SUPPLEMENTARY INFORMATION: In accordance with MAP-21 (Pub. L. 112-141),
this final rule amends FMVSS No. 225 \1\ and 213b \2\ to improve the
ease-of-use of child restraint anchorage systems. MAP-21 Section 31502
requires the Secretary of Transportation (NHTSA by delegation) to
improve the ease-of-use for lower anchorages and tethers in all rear
seat seating positions if such anchorages and tethers are feasible.
Section 31502 of MAP-21 states that the Secretary must issue a final
rule unless such an amendment to FMVSS No. 225 does not meet the
requirements and considerations set forth in subsections (a) and (b) of
section 30111 of title 49, United States Code (the National Traffic and
Motor Vehicle Safety Act (Safety Act)). NHTSA is issuing this final
rule, as directed by MAP-21, after determining that the rule meets the
requirements and considerations of section 30111(a) and (b) of the
Safety Act. This final rule also fulfils NHTSA's goal of improving the
usability of child restraint anchorage systems.\3\
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\1\ 49 CFR 571.225, ``Child restraint anchorage systems.''
\2\ The 2015 NPRM proposed changes to FMVSS No. 213; however,
NHTSA recently amended FMVSS No. 213 and issued FMVSS No. 213b for
plain language reasons relating to multiple compliance dates of the
amendments (88 FR 84514). NHTSA decided the requirements would be
easier to read and understand if the agency issued amendments
becoming effective on December 5, 2024, for FMVSS No. 213 and
December 5, 2026, for FMVSS No. 213b.
\3\ NHTSA's 2011-2013 Priority Plan. Link: <a href="http://www.regulations.gov/document/NHTSA-2009-0108-0032">www.regulations.gov/document/NHTSA-2009-0108-0032</a>.
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NHTSA published the notice of proposed rulemaking (NPRM) preceding
this final rule on January 23, 2015 (80 FR 3744). In this final rule
preamble, NHTSA is using the term ``child restraint anchorage system''
(CRAS) to refer to the full vehicle system \4\ that is designed for
attaching a child restraint system (CRS) to a vehicle at a particular
designated seating position (DSP).'' \5\ NHTSA also uses the term
``lower anchorages'' for the lower anchorage points of a CRAS. The
agency refers to the tether securement point as a ``tether anchorage.''
For the CRS, this preamble
[[Page 1289]]
uses the following terms to refer to the various parts of a child
restraint that connect to the CRAS, as appropriate: ``child restraint
system connectors'' (or ``CRS connectors''), ``lower anchorage
connector(s),'' ``tether anchorage connector,'' ``tether strap,'' and
``tether hook.''
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\4\ A full vehicle child restraint anchorage system has two
lower anchorages and one tether anchorage in a designated seating
position.
\5\ Many in the child passenger safety community refer to the
child restraint anchorage system as the ``LATCH'' system, an
abbreviation of the phrase ``Lower Anchors and Tethers for
Children.'' This term was developed by a group of manufacturers and
retailers soon after the 1999 final rule (64 FR 10786) to educate
consumers on the availability and use of the anchorage system and
for marketing purposes. ``LATCH'' has historically been used in
various field materials and by NHTSA to refer to the vehicle 3-point
child restraint anchorage system. However, the term has also been
used to refer to only the lower two anchorages of the system, or to
refer to the connectors of the child restraint system that attach to
the lower anchorages. Further, NHTSA understands many consumers
identify the tether anchorage solely with the ``LATCH'' system, and
thus mistakenly do not attach the CRS's tether strap when using the
vehicle belt system to attach a child restraint. As such, NHTSA has
chosen to avoid using the term ``LATCH'' in this document where
possible to avoid ambiguity.
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Table of Contents
I. Executive Summary
II. Statutory Authority
III. Summary of the NPRM
IV. High Level Summary of the Comments Received
V. Improving the Ease of Using Lower Anchorages
a. Attaching to the Lower Anchorages
b. Post-NPRM Research
c. Summary of Decision on Assessing Usability of Lower
Anchorages
d. Detailed Agency Decisions Regarding the Tools and Performance
Criteria
VI. Improving the Ease of Using the Tether Anchorage
a. Attaching to the Tether Anchorage
b. Tightening the Tether
c. Noticing the Tether Anchorage
d. Recognizing the Tether Anchorages
VII. Conspicuity and Identification of Vehicle Anchorages and CRS
Connectors
a. General Comments and Agency Responses
b. Lower Anchorage Marking Comments and Agency Responses
c. Tether Anchorage and Connector Marking Comments and Agency
Responses
d. Tether Anchorage Marking Comments and Agency Responses
VIII. Applying FMVSS No. 225 to Vehicles Currently Excluded
IX. Public Responses To Request for Comments and NHTSA's Views
a. Center Rear Seat--Dedicated, Shared or No Lower Anchorages
b. Third Row
c. Terminology
d. Recommendation for Tether Anchorage Use Regardless of Child
Weight
X. Housekeeping
XI. Lead Time and Phase-In
XII. Cost Benefit Analysis
XIII. Regulatory Notices and Analyses
I. Executive Summary
a. Introduction
This final rule amends FMVSS No. 225 to improve the usability
(ease-of-use) of the standardized CRASs required by the standard. Prior
to FMVSS No. 225, CRSs were anchored to a vehicle seat solely by the
seat belt. Because seat belts are primarily designed for passengers and
not child restraints, incompatibilities existed between seat belts and
CRSs. NHTSA issued FMVSS No. 225 in response to this problem to
optimize the safety performance and ease of the correct use of child
restraints through a dedicated CRAS. The standard aims to reduce the
likelihood of an anchorage system's failure and increase the likelihood
that CRSs are properly secured to achieve the CRS's safety benefits
during motor vehicle crashes.\6\
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\6\ 49 CFR 571.225, S1.
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The CRAS required by FMVSS No. 225 entails a 3-point system
consisting of two lower anchorages and a tether anchorage, designed for
attaching a CRS to a vehicle. Each lower anchorage consists of a 6-
millimeter (mm) diameter straight rod, or ``bar,'' onto which a CRS
connector can be attached.\7\ The two lower anchorage bars are
typically located at or near the seat bight (the area where a seat
cushion intersects with the seatback) in a position where they will not
be felt by seated adult occupants. The tether anchorage is a
permanently installed vehicle system to which a CRS tether hook can be
attached.\8\
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\7\ When NHTSA issued FMVSS No. 225, the agency also amended
FMVSS No. 213 to require child restraint systems to have the CRS
connectors permanently attached to each child restraint. In the case
of rear-facing child restraints with detachable bases, only the base
is required to have the components.
\8\ FMVSS No. 225 requires vehicles with three or more forward-
facing designated rear seating positions to be equipped with child
restraint anchorage systems at not fewer than two forward-facing
designated rear seating positions and a tether anchorage at an
additional designated rear seating position. If the vehicle has
fewer than three forward-facing rear designated seating positions,
fewer child restraint anchorage systems are required.
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CRASs meeting FMVSS No. 225 and child restraints meeting the
associated requirements of FMVSS No. 213 have been successfully
implemented in the fleet since the implementation of FMVSS No. 225.
According to a 2006 study by Decina, consumers who use the CRAS
generally like the system \9\ and prefer using lower anchorages to
attach child restraints to the vehicle over seat belt attachments. The
study also found that CRASs help reduce the incorrect installation of
child restraints (61 percent of CRSs installed with CRAS were securely
installed compared to 40-46 percent of CRSs that were securely
installed using seat belts).\10\ However, the study found many
consumers do not use CRASs because they do not know enough about the
systems.\11\
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\9\ Decina, L., et al., ``Child Restraint Use Survey: LATCH Use
and Misuse,'' December 2006, (``Decina study''), DOT HS 810 679,
Docket No. NHTSA-2006-26735. The Decina study is summarized in
Appendix A to the NPRM preamble.
\10\ Id.
\11\ Id.
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Gathered data also indicates that many consumers misuse the CRAS or
find aspects of it difficult to use. Specifically, in 2007 NHTSA held a
public meeting on CRAS to see how the systems could be improved.\12\
Attendees repeatedly stated that lower anchorages were often embedded
deep into the seat bight, making it difficult for consumers to reach
the lower anchorages and attach the lower anchorage connectors.
Attendees also indicated that it was difficult to attach lower
anchorage connectors to the lower anchorages because of surrounding
stiff cushions, stiff fabric/leather, or the proximity of seat belt
buckles. In response to comments received at the public meeting NHTSA
studied possible ways to improve the usability of CRASs.\13\ NHTSA used
the information obtained from these studies to assist in responding to
the 2012 Congressional mandate set forth in section 31502(b)(1) of MAP-
21 in 2012, publishing an NPRM on January 23, 2015, to commence
rulemaking to improve the ease-of-use of child restraint anchorage
systems.\14\
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\12\ Docket No. NHTSA-07-26833. A summary of the public meeting
can be found in Appendix B to the NPRM preamble.
\13\ NHTSA included plans to address the CRAS usability concerns
raised at the 2007 LATCH public meeting in its Vehicle Safety and
Fuel Economy Rulemaking and Research Priority Plan (2011-2013).
Docket No. NHTSA-2009-0108-0032.
\14\ Further background on the development of the NPRM can be
found in the NPRM preamble. NHTSA discusses its reasons for using
the UMTRI LATCH Usability study, infra, in section III of the NPRM
(80 FR 3748-3753).
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b. Summary of the Final Rule
This final rule adopts most, but not all, of the proposals in the
NPRM to improve CRAS ease-of-use. This final rule also adjusts several
provisions in response to comments received on the NPRM.
1. This final rule amends FMVSS No. 225 to enhance requirements for
the usability of CRASs. The final rule's requirements are based in part
on findings from the University of Michigan Transportation Research
Institute (UMTRI) about characteristics of the vehicle seat that
enhance the usability of CRASs (``LATCH Usability study'').\15\ This
final rule adopts a ``clearance angle'' for each lower anchorage of at
least 54 degrees (clearance angle relates to the clearance around a
lower anchorage from interfering parts that can make it difficult to
maneuver the CRS lower anchorage connector) and an ``anchorage depth''
limit (location of the lower anchorage within the seat bight)
[[Page 1290]]
of less than 25 millimeters (mm). Although the 2015 NPRM included an
``attachment force'' limit, NHTSA has decided not to adopt an
attachment force requirement in this final rule based on comments
received and additional study by NHTSA. This final rule's clearance
angle and anchorage depth limit requirements will substantially improve
consumer ease in using the lower anchorages of CRASs.
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\15\ Klinich et al., supra. Link: <a href="http://deepblue.lib.umich.edu/handle/2027.42/90856">http://deepblue.lib.umich.edu/handle/2027.42/90856</a>. The report was sponsored by the Insurance
Institute for Highway Safety (IIHS) for developing IIHS's rating of
the usability of the child restraint anchorage systems in various
vehicles. See IIHS Status Report: Vol. 47 No. 3, April 12, 2012.
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2. This final rule modifies the hand-held tools used to measure
clearance angle and anchorage depth proposed in the NPRM. Comments
received stated that the proposed tools yielded inconsistent results
and were hard to use. In response, NHTSA undertook several studies,
discussed below in this preamble, to refine the proposed tools and
validate their improved repeatability and reproducibility in
measurements. This final rule adopts these improved test tools.
3. This final rule restricts tether anchorages from being placed
under a vehicle seat or hidden under vehicle components other than a
marked tether anchorage cover. The rule also restricts how close the
tether anchorage can be from the child restraint, (a too-close tether
anchorage can make it impossible to tighten the tether strap properly),
but does not adopt the location requirements that were detailed in the
NPRM. Some vehicle manufacturers stated that the proposed requirements
were too restrictive, involved a procedure that was not executable in
certain vehicles, or would result in costly redesign. The procedure
adopted in this final rule is less restrictive than those proposed in
the NPRM, is clear to execute, and in some cases affects the re-
location of the tether by a shorter distance or not at all. NHTSA is
also giving more lead time coupled with a 3-year phase-in of the
requirements to lessen the burdens of redesigning vehicles and to
reduce costs.
4. This final rule amends FMVSS No. 225 to make tether anchorages
easier to use by standardizing the configuration of the anchorage such
that it is ``a rigid bar of any cross-section shape.'' However, in
response to comments, the rule allows vehicles with unique space
limitations in the vehicle interior, such as buses, light trucks, and
convertibles, to have flexible anchorages that can also be used as a
tether strap routing device.
5. This final rule standardizes the markings that will indicate to
consumers the location and presence of the lower anchorages and the
tether anchorage. These new markings are based on improved anchorage
marking designs developed by the International Standardization
Organization (ISO). Specifically, this final rule amends FMVSS Nos. 225
and 213b to require, among other things, vehicles and CRSs to use a
standardized symbol to more clearly identify vehicle anchorages and CRS
components that attach to those anchorages. With these markings all
consumers can easily look for the specific marks and ``match up'' the
symbols on the vehicle to the symbols on the child restraint.
6. This final rule amends FMVSS Nos. 213b to require the top tether
hook and attachment hardware on child restraint systems to be limited
in length, as proposed in the NPRM.
This preamble discusses these amendments and others in detail
below.
c. How This Final Rule Differs From the NPRM
Highlighted below are the main differences between the NPRM and
this final rule. More minor changes (e.g., how a tool is oriented
during a test) are not highlighted here but are discussed in the
sections relevant to the topic.
The final rule differs from the NPRM in the following ways:
<bullet> This final rule does not adopt the proposed requirement
for maximum attachment force of 178 Newtons (N) (40 lbf) to the lower
anchorages to improve ease-of-use. NHTSA worked to improve the
repeatability of the attachment force tool and conducted a
repeatability and reproducibility (R&R) study. Results showed that the
force measurements were not repeatable or reproducible enough to be
adopted because the force attachment tool measurements contain too much
variance.
<bullet> This final rule fine-tunes the proposed Clearance Angle
and Depth Tools to achieve greater R&R in measurements. The
improvements to the tools address comments on variability and
subjectivity of the measurements. The improved tools incorporate new or
additional instrumentation or features to enable consistent and non-
subjective measurements.
<bullet> This final rule specifies that the lower anchorage must be
located 25 mm or less within the seat bight instead of the 20 mm within
the seat bight proposed by the NPRM. This increase in depth measurement
takes into consideration the manufacturing variability across vehicles
of the same model.
<bullet> This final rule does not adopt the proposed requirement
for 165 mm minimum distance of a tether anchorage from a reference
point on a vehicle seat to provide enough clearance for tightening the
tether strap. Instead, this final rule requires the tether anchorages
for vehicle seats with no head restraint or with adjustable or
removable head restraints to be located outside of a zone bounded by a
325 mm radius sphere centered at the R-point of the vehicle seat and
truncated by a horizontal plane located 230 mm below the sphere's
center. This change was made to address multiple concerns from
commenters. For example, the new zone addresses the difficulty of
defining the proposed reference point (SB) and uses an already defined
reference point in the standard (R-point). This measurement also takes
into consideration the seat's depth to account for the distance that is
routed over the seat towards the CRS, addressing a concern raised by
one commenter. The new measurement required by this final rule will
result in fewer vehicle models requiring tether anchorage relocation.
Additionally, for those vehicle models requiring the relocation of
tether anchorages, the relocation distance will, in most cases, be
reduced. The final rule does not require vehicle seats with fixed head
restraints to comply with the minimum distance of a tether anchorage
from the R-point, as such seats do not have any elements that would
interfere with the installation and tightening of the tether. To reduce
cost burdens on the vehicles that will need redesign, we have extended
the lead time for manufacturers to comply by introducing a 3-year
phase-in that will begin on the first September 1 that is three years
after publication of the final rule.
<bullet> This final rule revises the proposed forward-most
allowable tether anchorage zone under the seat from the ``plane
parallel to the torso line passing through the rearmost point of the
bottom of the seat'' to a ``vertical transverse plane 120 mm rearward
of the seating reference point.'' Commenters stated that the proposed
allowable tether anchorage zone based on the rearmost point of the
bottom of the seat may not be objectively determined in some seat
designs. Additionally, commenters stated that some current seat designs
with easily accessible tether anchorages located slightly under the
back of the seat may not be compliant with the proposed tether
anchorage zone. This final rule's alternative measurement can be
objectively determined for all seat designs, will allow tether
anchorages that are on the seatback but still accessible, and will
prevent tether anchorages that are deep under the seat.
<bullet> This final rule provides exceptions to the NPRM's
originally proposed requirement that all tether anchorages be rigid
bars. Tether anchorages will not
[[Page 1291]]
be required to be rigid bars for buses with a GVWR less than or equal
to 4,536 kg (10,000 lb) and for vehicles with DSPs where the
``allowable tether zone'' in FMVSS No. 225 falls in an area that is
only accessible by removing a seating component of the vehicle. These
vehicles can be equipped with tether strap routing devices that can be
used as tether anchorages. Commenters stated that flexible tether
anchorages (that can also be used as routing devices) in vehicles such
as pick-up trucks are easy to use for installing CRSs but would no
longer be permitted under the proposed requirements for rigid tether
anchorages. If only rigid bar tether anchorages are permitted, the
allowable locations for these tether anchorages would be behind the
seatback where folding the seat or moving the seat forward is necessary
to access the tether anchorage. Such a seat design requires an
iterative tensioning of the tether to install a CRS, which is more
time-consuming and difficult. Therefore, the agency is continuing to
allow flexible anchorages in vehicle that cannot locate the tether
anchorage in the allowable zone.
<bullet> This final rule updates the tolerances and positioning of
lower and tether anchorages markings to that proposed in response to
comments received. This final rule increases the tolerances of the
position of the markings from that proposed in the NPRM and makes some
allowances on the position of the markings to accommodate a variety of
vehicle designs.
<bullet> This final rule adopts a 3-year phase-in period to comply
with the updated requirements in FMVS No. 225. The phase-in period
starts on the first September 1 that is three years after the
publication of the final rule. This additional lead time and phase-in
period will reduce potential tooling costs by allowing manufacturers
the opportunity to make required changes to subject vehicles during
their regular design update cycles.
d. Rulemaking Goals
The requirements of this final rule, aimed at increasing consumer
use of CRASs for the installation of CRSs, will make the CRASs more
conspicuous and easy to use.\16\
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\16\ NHTSA designed FMVSS No. 213 and No. 225 to require each
applicable child restraint to be able to attach to a vehicle seat by
way of the CRAS, and additionally by way of the seat belt
(continuing what was done prior to the standard, so that child
restraints could continue to be attached using the seat belt, which
is at every designated seating position in a vehicle).
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If CRASs becomes easier to use correctly, more consumers will
achieve a tight fit of the CRS in the vehicle, resulting in reduced
child head and torso excursions in motor vehicle crashes, and thus
fewer child head and torso injuries from crashes. The goal of this
rulemaking is supported by studies showing that many consumers are not
aware of or do not fully understand the CRASs available in their
vehicle. Specifically, the 2006 Decina study found that many consumers
did not know about CRASs, that CRASs were available in their vehicle,
the importance of using CRASs to install CRSs, or how to properly use
CRASs. The Decina study also found that users attempting to use CRASs
generally liked the systems, and that drivers with experience attaching
a CRS using a CRAS strongly preferred using a CRAS's lower anchorages
over seat belts. Moreover, the study found consumers were more likely
to install a CRS correctly using a CRAS than a seat belt. Finally, the
LATCH Usability study found that test subjects who correctly used the
lower anchorage hardware were 3.3 times more likely to achieve a tight
CRS installation than subjects who made errors using the hardware.
e. NHTSA's Determination of MAP-21 Requirements and Considerations
This final rule satisfies subtitle E, Section 31502 of the ``Moving
Ahead for Progress in the 21st Century Act'' (MAP-21). Section 31502(a)
requires NHTSA (by delegation of authority 49 U.S.C. 30111) to initiate
a rulemaking proceeding to improve the ease-of-use for lower anchorages
and tether anchorages in all rear designated seating positions if such
anchorages and tether anchorages are feasible. Section 31502(b)(1) of
MAP-21 states that, subject to exceptions, NHTSA (by delegation) must
issue a final rule. An exception is for an amendment to Standard No.
225 which ``does not meet the requirements and considerations set forth
in subsections (a) and (b) of section 30111 of title 49, United States
Code [the National Traffic and Motor Vehicle Safety Act (Vehicle Safety
Act)].'' As discussed below, NHTSA has made such a determination
regarding the final rule amendments to FMVSS No. 225 to improve the
ease-of-use of the CRAS.
The provision at 49 U.S.C. 30111(a) of the Safety Act authorizes
the Secretary (NHTSA, by delegation) to prescribe Federal motor vehicle
safety standards that are practicable, meet the need for motor vehicle
safety, and are stated in objective terms. ``Motor vehicle safety'' is
defined in the Safety Act as ``the performance of a motor vehicle or
motor vehicle equipment in a way that protects the public against
unreasonable risk of accidents occurring because of the design,
construction, or performance of a motor vehicle, and against
unreasonable risk of death or injury in an accident, and includes
nonoperational safety of a motor vehicle.'' \17\ This final rule meets
the need for motor vehicle safety because it would increase the
likelihood that CRASs and CRSs will be correctly used, thereby reducing
the risk of injury to restrained children in motor vehicle crashes.
This final rule improves the correct use of CRASs and CRSs by requiring
the lower anchorages and tether anchorage of the CRAS to be more
accessible, easy to use, and clearly labeled so that consumers can
easily identify and use them. This final rule is practicable because a
number of vehicle and child restraint models already meet the
requirements of the final rule. NHTSA is also providing a substantial
lead time to meet the requirements. Some vehicle seat designs will
change pursuant to the rule, but the redesigns would involve relatively
straightforward modifications to the existing vehicle materials (i.e.,
the seat cushion); most vehicles will not have to change the vehicle
structure. This final rule is objective because the requirements are
stated in unambiguous terms and assessed using tools and procedures
with demonstrated R&R.
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\17\ 49 U.S.C. 30102(a).
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49 U.S.C. 30111(b) specifies that, when prescribing Federal motor
vehicle safety standards, the Secretary (NHTSA, by delegation) must,
among other things, consider all relevant, available motor vehicle
safety information, consider whether a standard is reasonable,
practicable, and appropriate for the types of motor vehicles or motor
vehicle equipment for which it is prescribed, and consider the extent
to which the standard will further the statutory purpose of reducing
traffic crashes and associated deaths and injuries. NHTSA has
determined that this final rule is reasonable, practicable, and
appropriate for the types of motor vehicles and child restraint systems
for which it is prescribed. This final rule accounts for challenges
that buses and light trucks could have in meeting the proposed
requirement that all tether anchorages be rigid bars located in a
particular zone. Among other things, the rule permits these vehicles to
have tether strap routing devices that can be used as the tether
anchorage if the rigid bar is not feasible.
NHTSA considered existing industry standards and conducted
extensive research prior to the finalization of this
[[Page 1292]]
final rule to improve the tools and test procedures in existing
industry standards to ensure objectivity of the ease-of-use
assessments. NHTSA's assessments indicate that most vehicle models and
child restraints already comply with the requirements of the final
rule. For products that do not, the final rule provides ample lead time
for modifications to be implemented with little to no cost.
f. Estimated Costs and Benefits
The agency estimates that the adopted requirements for improved
usability of CRASs would not result in any increase in material cost
but would entail some redesign of vehicle seat features. In response to
the comments received, NHTSA is providing a 3-year phase-in period to
comply with the updated FMVSS No. 225 requirements. The phase-in period
starts on the first September 1 that is three years after the
publication of the final rule. We believe this approach would respond
to commenters' concerns and provide sufficient time for vehicle
manufacturers to accommodate any redesign of the vehicle seat and rear
shelf structures to meet this final rule in their normal course of
manufacture without a cost increase.
NHTSA estimates the cost of ISO markings for a set of lower
anchorages to be $0.07 and that for the tether anchorage to be $0.03.
The total incremental cost of equipping all CRASs with appropriate ISO
markings is about $760,000. The final rule also requires similar ISO
markings on child restraint anchorage connectors, for which the agency
estimates an incremental cost of $970,000. The cost of changing the
written instructions accompanying the vehicle or the CRS to explain the
ISO markings is expected to be negligible (<<$0.01). Therefore, the
total cost of the proposed rule is estimated to be $1.73 million.
These new usability requirements will assist in improving correct
(tight) installation and increase tether use. If there were a 5 percent
increase in correct installation using the lower anchors and a 5
percent increase in tether use, the agency estimates that the proposed
requirements would save approximately 3 lives and prevent 6 moderate to
higher severity injuries per year.
II. Statutory Authority
This final rule is issued under the Safety Act \18\ (49 U.S.C.
30101 et seq.) and MAP-21.
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\18\ National Traffic and Motor Vehicle Safety Act (Safety Act).
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Under the Safety Act, the Secretary of Transportation \19\ is
responsible for prescribing motor vehicle safety standards that are
practicable, meet the need for motor vehicle safety, and are stated in
objective terms.\20\ ``Motor vehicle safety'' is defined in the Safety
Act as ``the performance of a motor vehicle or motor vehicle equipment
in a way that protects the public against unreasonable risk of
accidents occurring because of the design, construction, or performance
of a motor vehicle, and against unreasonable risk of death or injury in
an accident, and includes nonoperational safety of a motor vehicle.''
\21\ ``Motor vehicle safety standard'' means a minimum performance
standard for motor vehicles or motor vehicle equipment.\22\ When
prescribing such standards, the Secretary must consider all relevant,
available motor vehicle safety information, and consider whether a
standard is reasonable, practicable, and appropriate for the types of
motor vehicles or motor vehicle equipment for which it is
prescribed.\23\ The Secretary must also consider the extent to which
the standard will further the statutory purpose of reducing traffic
crashes and associated deaths and injuries.\24\
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\19\ The responsibility for promulgation of Federal motor
vehicle safety standards is delegated to NHTSA. 49 CFR 1.95.
\20\ 49 U.S.C. 30111(a).
\21\ 49 U.S.C. 30102(a)(8).
\22\ 49 U.S.C. 30102(a)(9).
\23\ 49 U.S.C. 30111(b).
\24\ Id.
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MAP-21
MAP-21 (Pub. L. 112-141) incorporates Subtitle E, ``Child Safety
Standards.'' Subtitle E, section 31502(a), requires that not later than
1 year after the date of enactment of the Act, the Secretary (NHTSA, by
delegation) shall initiate a rulemaking proceeding to amend FMVSS No.
225 ``to improve the ease-of-use for lower anchorages and tethers in
all rear seat seating positions if such anchorages and tethers are
feasible.'' NHTSA published the NPRM preceding this final rule on
January 23, 2015. Section 31502(b)(1) of MAP-21 states that, subject to
exceptions, the Secretary must issue a final rule not later than 3
years after the date of enactment of MAP-21. An exception is for an
amendment to Standard No. 225 which ``does not meet the requirements
and considerations set forth in subsections (a) and (b) of section
30111 of title 49, United States Code [the National Traffic and Motor
Vehicle Safety Act (Safety Act)].'' \25\
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\25\ See 49 U.S.C. 31502(b)(2).
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NHTSA interprets section 31502(a) as directing DOT to initiate
rulemaking to improve the ease-of-use of lower anchorages and tether
anchorages currently required by FMVSS No. 225 if improved anchorages
are feasible.\26\ This final rule satisfies the mandate by adopting
requirements that will improve the ease with which consumers can access
and use the anchorages and improve the visibility of the anchorages so
that consumers can more easily identify them as parts of a CRAS.
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\26\ See 80 FR 3747 Section II. Statutory Mandate.
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NHTSA carefully considered the potential merits of requiring
additional CRASs in vehicles, with the NPRM requesting comment on
whether additional lower anchorages and tether anchorages should be
required in vehicles. Manufacturers commented that it is difficult to
have additional CRAS systems due to spacing and complex designs that
may increase misuse of the lower anchorages. Following careful
consideration and review of comments, NHTSA has determined the
available data does not support a safety need to require additional
CRASs or tether anchorages in vehicles already covered under FMVSS No.
225.
The NPRM also requested comment on the merits and feasibility of
installing tether anchorages and lower anchorages in vehicles excluded
from such requirements by the issuance of FMVSS No. 225 in 1999. This
final rule removes the current exclusion from tether anchorages for
convertible vehicles \27\ and vehicles described in FMVSS No. 225 S5(e)
from having to provide lower anchorages and a tether anchorage in rear
designated seating positions. This decision was made based on the
agency's determination that installing the tether and lower anchorages
in these previously excluded vehicles is practicable \28\ and, given
data showing the benefits of tether anchorages and CRASs, will meet the
need for safety. These topics are discussed in greater detail below.
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\27\ S5(a) of FMVSS No. 225.
\28\ There are vehicles that have solved the challenges of
providing lower anchorages and tether anchorages, proving that
solutions are feasible.
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Section 31502 gives NHTSA no discretion in issuing a final rule if
a rule would meet the conditions set forth in MAP-21. As discussed
above, NHTSA has determined that amending FMVSS No. 225 as set forth in
this final rule meets the requirements and considerations established
in subsections (a) and (b) of 49 U.S.C 30111 and are feasible.
Accordingly,
[[Page 1293]]
NHTSA is issuing this final rule as mandated by MAP-21.
III. Summary of the NPRM
The NPRM proposed to reduce the physical difficulties associated
with attaching a child restraint to the lower anchorages and to the
tether anchorage, and to improve how easily a consumer can identify the
anchorages and match them up with parts on a child restraint system.
Regarding the physicality of using the vehicle's CRAS, the proposed
changes to FMVSS No. 225 were based on the findings in UMTRI's LATCH
Usability study, supra, about characteristics of the vehicle seat that
enhance the usability of CRASs. NHTSA proposed the limits on the
clearance angle, attachment force, and the depth of the anchorage in
the seat bight to address the ease-of-use problems described in the
Decina study, supra, and expressed by various attendees to the 2007
public meeting. The NPRM's proposals are further summarized below.
Ease of Using Lower Anchorages
Although FMVSS No. 225's current requirements for the location of
lower anchorage bars near the seat bight intend for the bars to be
accessible, some consumers find it difficult to use the bars. NHTSA
proposed new requirements for the bars to improve ease-of-use: a
minimum ``clearance angle'' of 54 degrees (clearance angle relates to
the clearance around a lower anchorage from interfering parts that can
make it difficult to maneuver the CRS's lower anchorage connector), a
maximum ``attachment force'' of 178 N (40 lbf), and an ``anchorage
depth'' of less than 20 millimeters (mm)). These are the ease-of-use
specifications the UMTRI LATCH Usability study found to correlate with
correct child restraint installation by test subjects.
In accordance with the LATCH Usability study, NHTSA proposed the
use of three new tools: one to measure clearance angle, another to
measure attachment force, and a third to determine anchorage depth.
Clearance angle would be measured by a tool based on a Society of
Automotive Engineers (SAE) draft J2893 recommended practice that
attaches to the lower anchorages. Attachment force would be measured by
a force gauge. Anchorage depth would be measured by a simple tool,
similar to one UMTRI developed, with a hook-type CRS connector marked
every 20 mm. The NPRM also proposed to incorporate by reference drawing
packages into FMVSS No. 225.
Ease of Using Tether Anchorages
FMVSS No. 225 currently requires tether anchorages to be located in
a specified zone and to be accessible without the need for any tools
other than a screwdriver or coin. To improve the usability of the
tether anchorage, NHTSA proposed the following requirements to make it
easier for consumers to recognize and access the anchorage.
<bullet> The NPRM proposed to reduce the zone in which a tether
anchorage must be located, to prevent tether anchorages from being
placed deep under a vehicle seat.
<bullet> The tether anchorages would have to be accessible without
the need for any tools and without folding the seatback or removing
carpet or other vehicle components. The tether anchorage could be
covered with a cap, flap, or cover, provided that the cap, flap, or
cover is specifically designed to be opened, moved aside, or to
otherwise give access to the anchorage without the use of any tools and
is labeled with a specific symbol indicting the presence of the tether
anchorage underneath.
<bullet> Some tether anchorages are too close to a structure, such
as a head restraint, to allow tightening of the tether strap. NHTSA
proposed to specify a minimum 165 mm (6.5 in) distance from a specified
reference point on the vehicle seat to the tether anchorage so that
adequate clearance will be provided for tightening of the tether strap.
<bullet> Currently, there are some tether anchorages made from
flexible webbing. NHTSA proposed to require that the tether anchorage
be a standardized rigid bar so consumers could more easily recognize
and find it.
<bullet> NHTSA proposed to limit the length of the CRS tether
hardware assembly (which consists of a tether hook and hardware to
tighten and loosen the tether strap) to 165 mm (6.5 in) so that the
tightening mechanism can be easily used in the clearance space around a
tether anchorage.
Enhanced Ability To Identify Anchorages
In relation to consumers' seeing or recognizing the anchorages,
FMVSS No. 225 currently requires the lower anchorage bars to be
visible, or that the vehicle seat back be marked showing the location
of the bars. To improve consumers' ability to see, recognize, and use
lower anchorages, NHTSA proposed to require that motor vehicles be
marked with a standardized ISO-developed marking near the location of
each lower anchorage bar even when the lower anchorage is visible.
Similarly, tether anchorages would be marked with the ISO-developed
marking. To complement these markings, NHTSA proposed that child
restraints bear the same ISO marking on the lower anchorage connectors
on the child restraint system and on the tether hook or tether strap,
so consumers could be taught to match up the symbols when they attach a
CRS.\29\
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\29\ The NPRM also proposed to require vehicle and child
restraint manufacturers to provide written information (e.g., in
owners' manuals) explaining the meaning of the ISO markings.
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IV. High Level Summary of the Comments Received
NHTSA received submissions from 30 entities. The commenters fell
into the following general categories: vehicle manufacturers or
associations (the Alliance of Automobile Manufacturers (Alliance),
Association of Global Automakers (Global),\30\ Ford Motor Company
(Ford), General Motors Company (GM), American Honda Motor Co., Inc.
(Honda), Fiat Chrysler Automobiles U.S. (Chrysler),\31\ Toyota Motor
North America (Toyota), Porsche Cars North America, Inc. (Porsche), and
Hyundai Motor Company (Hyundai)); child restraint manufacturers (the
Juvenile Products Manufacturers Association (JPMA), Britax Child
Safety, Inc. (Britax), Dorel Juvenile Group (Dorel), and Graco
Children's Products, Inc. (Graco)); suppliers (Motor and Equipment
Manufacturers Association (MEMA), and HSM Transportation Solutions,
Inc. (HSM)); auto dealers (National Automobile Dealers Association
(NADA)); forensics experts (ARCCA); consumer advocacy groups (Advocates
for Highway and Auto Safety (Advocates), Safe Kids Worldwide (Safe
Kids), Safe Ride News (Safe Ride News); research-associated
organizations (University of Michigan Transportation Research Institute
(UMTRI), Insurance Institute for Highway Safety (IIHS), MGA Research
Corporation (MGA), Consumer Union \32\); and other (including private
individuals).
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\30\ The Alliance and Global later merged and became the Auto
Innovators. This document refers to these commenters in the name in
which the comment was submitted.
\31\ Fiat Chrysler Automobiles U.S. is now Stellantis North
America.
\32\ Consumers Union is the public policy and advocacy division
of Consumer Reports.
---------------------------------------------------------------------------
There was almost unanimous agreement for improving the ease-of-use
of CRASs. However, commenters varied in their support for specific
requirements in the proposal. Many vehicle manufacturers expressed
concern about the extent of changes needed to meet some of the
[[Page 1294]]
requirements. Specifically, the manufacturers expressed concerns over
extensive redesign to relocate tether anchorages, costs of relocating
the tether anchorage, and challenges of meeting some of the lower
anchorage requirements given the involvement of soft seating surfaces.
Some manufacturers stated there was no need to specify all three
requirements (clearance angle, attachment force, and anchorage depth).
Suppliers urged NHTSA to provide more flexibility in marking vehicle
seats to identify lower anchorage locations so suppliers could avoid
extensive redesigns that would impose costs on suppliers and vehicle
manufacturers. Several vehicle manufacturers stated that the clearance
angle, attachment force, and anchorage depth test tools did not produce
repeatable or reproducible measurements, stating the proposed test
procedures were ambiguous and could not be followed. Vehicle
manufacturers generally objected to the proposed 3-year lead time as
insufficient to account for necessary changes. Many vehicle
manufacturers asked for a phase-in of the requirements.
Commenters split on the issue of removing certain vehicle
exemptions in FMVSS No. 225, such as the exclusion of convertible
vehicles from the requirement to provide tether anchorages (S5(a)), or
vehicles described in S5(e) of the standard from having any CRAS. A
vehicle manufacturers' association and vehicle manufacturers responding
to the issue were generally opposed to removing the exemptions.
Consumer advocates and research organizations strongly supported
removing the exemptions.
Many consumer advocates and research groups supported the NPRM but
contended the proposal should go further to improve the ease-of-use of
the anchorage systems. Consumer advocates and individuals described
numerous problems seen in the field that they believed should be
addressed. Overall, child restraint manufacturers and private
individuals supported the proposal.
Many commenters responded to NHTSA's questions posed in Section X
of the NPRM (80 FR 3764). Included in this section were questions about
whether there were safety concerns about using a ``simulated'' CRAS in
the rear center seating position.\33\ Most commenters concurred they
did not see safety issues raised using simulated CRASs in rear center
seating positions, provided the child restraint and vehicle
manufacturer at issue supported such use. NHTSA also asked whether its
education materials should recommend that tethers should be used for
all children regardless of the child's weight in the child restraint,
based on data indicating inherent benefits stemming from the use of a
tether.\34\ Most commenters on the issue supported the agency's
recommendation that tethers should be used by all children regardless
of weight, but one commenter (the Alliance) was opposed due to the
current strength requirements in FMVSS No. 225, which limit the forces
a tether anchorage can hold.
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\33\ A ``simulated'' child restraint anchorage system consists
of the inboard lower anchorages of the CRAS in the two outboard
seating positions and the tether anchorage in the center seat. NHTSA
explained in the NPRM preamble that available data indicate that
simulated CRASs appear crash-worthy and acceptable. Given these
data, the agency sought comment on whether NHTSA should encourage or
require CRS and vehicle manufacturers to include, in instruction
manuals, statements that endorse the use of simulated CRASs in the
rear center seating position to consumers who wish to place a CRS in
that center position.
\34\ That is, even if the tether or anchorage broke in a severe
crash, the tethering would have attenuated some of the crash forces.
---------------------------------------------------------------------------
Many commenters provided input on issues that were outside of the
scope of the rulemaking. NHTSA may consider these ideas for possible
future updates to FMVSS No. 213 and/or No. 225, but generally will not
further address comments outside the scope of the rulemaking in this
document.
V. Improving the Ease of Using Lower Anchorages
a. Attaching to the Lower Anchorages
The NPRM proposed ease-of-use requirements to ensure that vehicle
manufacturers produce lower anchorages that: (a) have sufficient
clearance around each lower anchorage for consumers to maneuver the CRS
connector to attach to the lower anchorage (``clearance angle'' of 54
degrees or more); (b) are located such that the CRS connector can be
attached to the bar without applying excessive force (``attachment
force'' 178 N (40 pounds (lbf)) or less); and, (c) are not too deep
within the seat bight so they are easily accessible (``anchorage
depth'' twenty millimeters (mm) or less from the outer surface of the
seat bight).
General Comments
Commenters varied in their views about the proposed clearance
angle, attachment force and anchorage depth requirements. Consumer
advocates expressed general support for the proposed lower anchorage
usability requirements. Advocates for Highway and Auto Safety
(Advocates) stated that the strengthening of FMVSS No. 225 through the
proposed revisions will likely result in more children being properly
restrained. Advocates concurred with the agency's view that improvement
in ease-of-use of the CRASs will increase use of CRSs and proper child
restraint system installation, which will in turn improve child safety.
Consumers Union supported the NPRM because, in their opinion, CRASs
provide an easier and more secure installation than seat belts.
IIHS strongly supported the NPRM, stating that IIHS confirmed
UMTRI's findings in the real world using data from Safe Kids' car seat
checkpoints from records of more than 14,000 child restraint
installations. IIHS found that anchor depths less than 4 cm, clearance
angles greater than 54 degrees, and attachment forces less than 178 N
(40 lbf) were associated not only with correct use, but also with use
of the anchorage system. While the commenter suggested the attachment
force tool could be improved, IIHS supported incorporating the proposed
measures into FMVSS No. 225. IIHS stated the proposed thresholds are
supported by real-world and laboratory data.
In contrast, many vehicle manufacturers expressed concerns about
the proposed requirements for lower anchorages. They expressed concern
about the extent of changes needed to meet some of the requirements and
the difficulties in consistently meeting requirements involving
measurements on soft materials like foam and cushions. The Alliance
supported the goal of establishing ease-of-use measurements for the
lower anchorages but did not agree with the proposed requirements and
test methods. The Alliance commented that only an anchorage depth
requirement is needed. It stated that the LATCH Usability study showed
the measurement of attachment force and clearance angle serve as
surrogates for anchorage accessibility. The commenter stated vehicles
with anchorages deeper in the seat bight generally had a smaller
clearance angle and higher attachment force in the study and that more
visible anchorages had larger clearance angles and lower attachment
forces, making the child restraint attachment step easier to
accomplish.
The Alliance stated that, since the proposed requirements for
anchorage location (anchorage depth) will expose the lower anchorages
in the vehicle, it can be expected that the attachment forces will be
lowered and the clearance angles will increase by design, making the
attachment force measurement and clearance angle measurement
unnecessary. Similarly, Fiat Chrysler
[[Page 1295]]
Automobiles U.S. (FCA) \35\ stated that clearance angle, force, and
anchorage depth are mutually inclusive and supported the Alliance's
position that relocating anchorages further forward in the vehicle will
generate similar results to the proposed requirements. FCA recommended
removing the attachment force and clearance angle criteria.
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\35\ FCA changed its name in 2020 to Stellantis. This preamble
refers to the commenter by its name on the comment, FCA.
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Comments Specific to the Tools
The NPRM proposed to assess clearance angle, attachment force, and
anchorage depth using a set of specialized tools based on the tools
used in the UMTRI study. Prior to the NPRM, NHTSA evaluated the
proposed procedures and tools in 10 vehicles, model years (MY) 2005-
2013, and concluded that the procedures appear objective and
repeatable.\36\ Notwithstanding the agency's data, several vehicle
manufacturers raised concerns about the usability of the proposed test
tools and questioned the repeatability and reproducibility (R&R) of
test tools measurements and recommended more refinement of the tools.
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\36\ NHTSA Technical Report, ``Evaluation of LATCH Usability
Procedure,'' Docket No. NHTSA-2014-0123-0005.
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Clearance Angle Tool (CAT)
Clearance angle relates to the open space around a lower anchorage,
free from interfering seat components. Interfering components can make
it difficult to maneuver and attach a CRS lower anchorage connector. A
clearance angle requirement facilitates easier attachment of a CRS
lower anchorage connector by ensuring surrounding components do not
impede access to the anchorage.
NHTSA proposed a clearance angle measurement tool, illustrated in
figure 1 in the NPRM, for this final rule. That clearance angle tool
(CAT) includes a load cell with a handle to measure the applied
vertical force on the tool and a potentiometer to measure the angle
achieved with respect to the horizontal plane by the tool during the
force application. In the proposed test procedure, the CAT is attached
to a lower anchorage. A vertical force of 67 N (15 lbf) is applied to
the tool. The angle the tool measures (with respect to the horizontal)
when that force is applied is the ``clearance angle.'' The NPRM
proposed to adopt a clearance angle requirement of not less than 54
degrees, as supported by the findings of the LATCH Usability study.
[GRAPHIC] [TIFF OMITTED] TR07JA25.026
Some of the Alliance members commented on their experience with the
SAE Prototype and UMTRI clearance angle test devices. The members
stated they found those devices difficult to use and not sufficiently
repeatable. GM and FCA commented that oscillations caused by the free-
hanging weight attached to the rotary potentiometer resulted in non-
repeatable measurements. GM recommended replacing the rotary
potentiometers on the CAT with a digital inclinometer connected to a
data acquisition system. FCA commented that without real-time readout
of the vertical force applied, the operator will always overshoot/
undershoot the specified vertical load. Similarly, GM recommended
adding a means of indicating the force to the operator during the
measurement process so that the operator is notified when 67 N (15 lbf)
is achieved. GM and the Alliance recommended a small diameter
cylindrical style load cell with a lower range of measurement. GM also
stated that the multiple pivot points between the handle and the load
cell and between the load cell and the main body should be reduced to a
single pivot at attachment to the main body.
GM stated that, in some cases, it is difficult to apply the
vertical force due to interference with the seatback. FCA commented
that an operator will have difficulty maintaining 67 N (15 lbf) of
vertical force even if there was a real time display of the vertical
force. GM recommended that the handle pivot point to the main body on
the tool be moved farther from the connection to the lower anchorage to
allow more
[[Page 1296]]
clearance between the load cell and the seatback. GM indicated that
eliminating this interference should improve the repeatability of the
process. GM added that the equivalent moment can be applied by
specifying a lower force along with the increased moment arm.
Attachment Force Tool (AFT)
Vehicle manufacturers raised concerns that the attachment force
tool did not provide repeatable or reproducible results. Ford suggested
that NHTSA include in FMVSS No. 225 language that would permit an
average of several trials (i.e., five trials of each anchorage) as
criteria for compliance. Ford and the Alliance stated that the
repeatability of this test is very dependent on operator skill and
experience and not adequately repeatable and reproducible when used by
different operators in different labs.
The Alliance explained that many vehicle models feature lower
anchorage designs that include either a cover or a slit in the seat
cushion that allows access to the anchorage bar. Assuming that these
types of design are not prohibited by the new proposed maximum
attachment force requirement for lower anchorages, the Alliance
recommended that the test be rerun if the test device becomes caught in
the slit or cover.
GM commented that the AFT does not provide real-time feedback,
making it difficult to ensure the operator performs the insertion force
measurement at a consistent angle with the 0-45-degree range specified.
GM noted that this would be particularly important if the trim
interferes with insertion of the tool. GM added that the operators
found the AFT angle difficult to control with the short T-handle (see
figure 2) while trying not to touch the tool beyond the load cell. GM
found that a digital inclinometer was helpful in observing the angle
and improved its confidence in the force data being collected. GM
recommended that the rotary potentiometer be replaced with a digital
inclinometer including a real-time readout for the operator and a
signal output for data acquisition. GM also suggested that the T-handle
be replaced with a longer axial handle to improve control of the
insertion angle and to avoid touching the tool along the load path.
[GRAPHIC] [TIFF OMITTED] TR07JA25.027
GM commented that the AFT does not indicate to the operator that
the switch used to detect full engagement of the tool on the anchorage
bar has been activated. GM explained that this lack of an indication
could result in a ``no switch closure'' event, and that the peak
attachment force prior to bottoming out cannot be determined if this
happened. GM added that if the AFT was not sufficiently perpendicular
to the anchorage bar, it would be possible to mechanically bottom out
the tool without closing the switch and that the perpendicular
requirement is dependent on the distance the slide pin must travel
before activating the switch. Additionally, GM stated that, depending
on the lower anchorage style in the vehicle, particularly for non-
visible anchorage bars, it can be difficult to determine
perpendicularity.
GM requested that the current tool be revised to allow a larger
tolerance to the range of perpendicularity, as a child restraint
anchorage connector may be attached at a larger range of angles than
the current tool design. GM suggested that this goal may be
accomplished by lengthening the slide pin or increasing the thickness
of the slide tab and that either solution will allow the slide tab to
close the switch earlier during anchorage bar engagement and increase
the perpendicularity tolerance. GM also recommended that an LED be
included on the tool to indicate to the operator when the switch is
closed.
GM also commented on the oscillations caused by the free-hanging
weight attached to the rotary potentiometer. GM noted that, depending
on the timing, the angle value at the time of switch closure could be
very close to a maximum or a minimum of an oscillation. GM explained
that in the example in figure 2 of its comment submission,\37\ the
oscillation is within the 0 to 45 degree force application range
specified in the proposal; however, these oscillations can be
eliminated by the utilization of a digital inclinometer. GM recommended
that the rotary potentiometer be replaced with a digital inclinometer
that includes a real-time readout for the operator and a signal output
for data acquisition. GM added that the rotational freedom of motion of
the AFT makes it difficult to control without touching the tool beyond
the load cell and potentially altering the force measurement. GM also
noted that the wiring to the load cell is susceptible to damage due to
its location relative to
[[Page 1297]]
the handle used to apply the force.\38\ GM recommended that an in-line
load cell with a threaded attachment between the main body and the
handle be adopted to alleviate these issues.
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\37\ NHTSA-2014-0123-0056.
\38\ Figure 3 of GM's comments can be found in Docket No. NHTSA-
2014-0123-0056.
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Similarly, FCA commented that the potentiometer attached to the
weight that is allowed to swing freely to capture the angle causes
oscillations in the recorded angle, that at the point in time when the
switch is triggered the attachment force increases drastically, the
operator's rate of force application can influence the results, and
that the AFT can interact with the seat cushion.
Global requested that lateral and vertical motions with the
proposed tool be allowed prior to the application of the insertion
force perpendicular to the center of the anchorage bar to represent
typical actions taken by the consumer when attaching a child restraint
to the lower anchorages.
IIHS stated that the agency's proposed changes to the AFT should
improve repeatability of measurements over the tools used in the
original IIHS/UMTRI research. IIHS provided the following two concerns:
1. IIHS and UMTRI stated the recorded attachment force should be
the peak force from initial engagement with the seat cushion until full
engagement of the tool on the lower anchorage. IIHS added that for some
vehicles the peak force occurs as the tool is inserted between the
cushions. IIHS stated such a peak force will not be captured when
following the proposed protocol because the AFT records the force only
at full engagement with the lower anchorage.
2. IIHS explained that the proposed changes to the tool do not
address the off-axis vertical force required to align the tool with the
lower anchorage.\39\ IIHS noted this vertical force was not measured in
NHTSA's evaluation. Instead, the force was assigned subjective ratings,
making it difficult to standardize the measurement procedure and
limiting R&R. IIHS noted it had developed a lower anchorage attachment
force tool \40\ that eliminates the need for additional vertical or
lateral forces. This IIHS-developed tool replaces the slide pin, slide
tab, and spring assembly with a square cross-section guide rod with a
convex notch that prepositions the tool, aligning it with the lower
anchorage bar before the force is applied. IIHS added that the new tool
replaces the original depth gauge, as the depth scale is inscribed on
the IIHS revised tool.\41\ IIHS encouraged NHTSA to make further
refinements to the attachment force tool to remove the need for off-
axis forces to properly align with the lower anchorage bar.
---------------------------------------------------------------------------
\39\ Evaluation of LATCH Usability Procedure, Louden et al.,
2014.
\40\ IIHS provided drawings of the new tool and a more detailed
description of its use in its comments. See <a href="http://www.regulations.gov/comment/NHTSA-2014-0123-0020">www.regulations.gov/comment/NHTSA-2014-0123-0020</a>.
\41\ Cicchino JB, Jermakian JS. ``Vehicle characteristics
associated with LATCH use and correct use in real-world child
restraint installations.'' Journal of Safety Research. 2015 June.
<a href="http://www.iihs.org/topics/bibliography/ref/2068">www.iihs.org/topics/bibliography/ref/2068</a>.
---------------------------------------------------------------------------
Hyundai commented that the proposed AFT did not represent the
hardware currently used in CRSs in the market. Hyundai stated it
observed 100 percent of forward facing/convertible child seats sold at
a retail store it visited are either the Safeguard clip system \42\ or
a simple hook. Hyundai noted the AFT has an exaggerated flat front face
that requires more effort to insert into the seat bight for attachment.
Hyundai also noted the attachment slot of the tool is not tapered,
potentially leading to false readings if not properly engaged with the
attachment bar. Hyundai performed a comparison evaluation with the
proposed tool and found that the force was reduced by 20-50 percent
when using a Safeguard attachment clip common in the industry. Hyundai
pointed out that CRS manufacturers have already found a solution for
increasing ease-of-use in attaching hardware by only using the
Safeguard clip system connectors or a simple hook system.
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\42\ Safeguard is a brand that produces push-on-type lower
anchorage connectors.
---------------------------------------------------------------------------
Anchorage Depth Tool (ADT)
Anchorage depth refers to how deeply the lower anchorages are
embedded in the vehicle seat (usually in the seat bight or seatback).
The LATCH Usability study found that an anchorage depth of less than 20
mm within the seat bight is associated with a significantly higher rate
of correct lower anchorage use than anchorage depths of 20 mm or more.
NHTSA proposed a requirement for each lower anchorage to have an
anchorage depth of less than 20 mm, as measured by a specially designed
lower anchorage depth tool (ADT). The proposed ADT incorporates a hook-
type CRS connector (see figure 3). The 20 mm distance is marked on the
tool. In a compliance test, the tool would be attached to a lower
anchorage. The NPRM proposed that the 20 mm mark would have to be
visible from a vertical longitudinal plane passing through the center
of the bar, along a line making an upward 30-degree angle with a
horizontal plane, without the technician manipulating the seat cushions
in any way.
[GRAPHIC] [TIFF OMITTED] TR07JA25.028
The Alliance explained that the current requirements for FMVSS No.
225 are based on the visibility of the lower anchorages around the soft
trim and that the current FMVSS No. 225 does not place the vehicle
development process at risk as the standard gives manufacturers the
option to certify the vehicles by adding seat cover markings if the
lower anchorage is not visible. The Alliance stated anchorage depth in
the current regulation is defined relative to a reference point, ``Z''
on the child restraint fixture (CRF), and the rearward-most location is
defined in
[[Page 1298]]
Section 9.2.2(a) as: ``Not more than 70 mm behind the corresponding
point Z of the CRF, measured parallel to the bottom surface of the CRF
and in a vertical longitudinal plane, while the CRF is pressed against
the seatback by the rearward application of a horizontal force of 100 N
at point A on the CRF'' and that section S9.2.2(b) requires that the
anchorage be located ``Not less than 120 mm behind the vehicle seating
reference point.'' The Alliance explained that these two requirements
``in essence'' create the fore/aft ``zone'' for anchorage placement
with respect to the seating reference point and the positioned CRF. The
Alliance stated that during initial design of a vehicle, a virtual CRF
is placed on the nominal seat to define the maximum anchorage depth and
that this process locates the anchorages relative to defined hard
points and ensures that the final anchorage location will be compliant
to the regulation. The Alliance added that the application force of 100
N allows for the variation of foam and trim in a production vehicle.
Difficulty Meeting the Current Lower Anchorage Location Requirements
and the Proposed Anchorage Depth Requirement
The Alliance explained that with certain current vehicle and seat
designs, it is challenging to balance the maximum distance that the
anchorage can be from the Z-point on the CRF with the 120-mm minimum
distance the anchorage can be from the seating reference point (SgRP).
The Alliance added that it may be difficult to meet the proposed lower
anchorage depth requirements without violating the minimum distance the
anchorage can be located from SgRP (S9.2.2(b)). The Alliance questioned
the agency's conclusion that because the proposed anchorage depth
specifies an anchorage must be less than 20 mm deep into the seat
bight, lower anchorages will be able to meet the proposed requirement
without conflicting with S9.2.2(b). The Alliance disagreed with NHTSA's
conclusion, stating that (1) it does not consider the trim surface
variation described above, and (2) it assumes all lower anchorages are
located at the bight line, which is often not the case in vehicles with
high bight lines.
Difficulties in the Design Process for Ensuring Compliance With the
Proposed Lower Anchorage Requirements
The Alliance and FCA explained that the seat development process
begins with virtual modeling tools used to establish the Vehicle
Occupant Package (VOP) ``hard points,'' such as h-point, torso angle,
seat belt anchorage locations, seat structure dimensions, etc., as well
as the location of the lower anchorages. The Alliance and FCA added
that these VOP ``hard points'' are established to ensure the final
vehicle package will conform to all regulatory requirements while
supporting customer-driven objectives such as comfort, seat adjustment
forces, etc., for the seat design.
The Alliance and FCA added that the production seat contour cannot
be developed exclusively in the virtual design space and that design
models cannot adequately capture the complex interaction of foam and
trim tension, folding actuation clearance, and comfort requirements.
The Alliance noted that in the typical vehicle development process, the
seat trim outline (STO) begins in the CAD design space and then matures
through several phases of physical properties to allow incremental
evaluation of the VOP dimensions, occupant comfort, seat folding/
adjusting efforts, and overall appearance.
FCA explained that early seat development properties are built
using skived foam (a foam cut from a solid block of foam) and that
while these properties allow early evaluations of customer driven
factors such as seat comfort, they are only directionally
representative of final seat designs. FCA added that this is because
skived foam does not have the same force/displacement properties of
production cast foam and that production foam is produced using a
molding process that results in a ``skin'' at the surface of the foam
and a variable density and stiffness that cannot be mimicked by skived
foam (which has a constant density and stiffness). As a result, FCA
explained it cannot accurately predict child seat installation efforts
with the accuracy and confidence necessary for regulatory compliance.
The Alliance and FCA stated that the virtual seat design process
lacks the material properties necessary to predict lower anchorage
attachment force with the accuracy necessary to guarantee regulatory
compliance and that vehicle manufacturers will run the risk of late
changes to the product design that will significantly increase design,
manufacturing, and testing costs.
The Alliance and FCA recommended that the agency investigate
alternatives to those in the proposal, including dimensional reference
from a CRF, to determine a more objective method of measurement that
will accomplish the associated ``ease-of-use'' goal. FCA stated this
approach will accomplish the goal of relocating anchorages closer to
the seat bight, while still using proven design and compliance
measurement processes.
FCA stated that while it supports the overall goal of increasing
the ``ease-of-use'' of child restraint systems for caregivers, the
proposed requirements and test methods are too dependent on ``soft''
seat features like trim and foam. Similarly, the Alliance stated that
the proposed method is overly sensitive to foam stiffness and the
production variability between trim surface and the lower anchorages
could exceed 20 mm.
Ford stated it does not agree that seat design changes needed to
meet the proposed lower anchorage requirements can be accomplished
through steps such as cutting larger open areas in the seat foam
surrounding the lower anchorage bars, as stated by NHTSA in the NPRM.
Ford explained that the manufacturing process for seat cushions doesn't
typically involve secondary cutting operations. Ford also stated that
design changes to meet the proposed requirements would require
modifications to foam tooling. Ford explained these modifications could
require inserts and separate compartments in the tool to locally revise
the density of the foam and that any local voids in the cushion or
seatback to provide clearance to anchorages would require a more labor-
intensive process to sew trim covers to achieve acceptable appearance
and craftsmanship. Ford also explained that since the system
characteristics are evaluated after the seat is built, the design
process will be iterative, and won't be fully understood until it
fabricates the assessment tools and conducts evaluations of existing
vehicles.
Ford stated that, at minimum, the proposed requirements would
require seat cushion, back foam, and trim changes to locally modify the
foam density in the area of the lower anchorages. Ford added that lower
anchorage bars in some vehicles may require modification so that the
anchorages extend further forward in-vehicle.
Subjectivity Reading Angle and ADT Angle During Measurement
FCA expressed concerns that the angle of the line of sight for
measuring the lower anchorage depth using the ADT can vary due to the
parallax effect and therefore the lower anchorage depth measurement is
user-dependent and lacks objectivity. Similarly, GM explained that the
ADT measurements are subjective in some cases, such as when overlapping
trim opening is
[[Page 1299]]
present.\43\ GM requested clarification of the procedure regarding trim
covering or surrounding trim being displaced by the tool and the angle
of the tool during determination of the depth measurement. The Alliance
stated there were differences between the UMTRI LATCH Usability study
and the NPRM ADT measurements. The Alliance noted that the UMTRI Study
specified no tension on the hook, which implies that the ADT will lie
on the seat cushion, while the Vehicle Research and Test Center (VRTC)
study was kept approximately parallel with the seat cushion. The
Alliance added that S9.2.2(a) did not specify any tension to be
maintained in the ADT, so it is implied that the tool would lie on the
seat cushion when making the measurement. GM recommended that the test
procedure require that the tool be kept parallel to seat cushion when
reading the depth measurement.
---------------------------------------------------------------------------
\43\ Shown on figure 8 of GM's submitted comments in Docket No.
NHTSA-2014-0123-0056.
---------------------------------------------------------------------------
Repeatability
FCA expressed concern regarding the tool's R&R during two different
ex parte meetings with NHTSA.\44\ During the September 21, 2015,
meeting, FCA presented two R&R studies showing the measurements with
the force and clearance angle tools had poor repeatability and
reproducibility. FCA recommended NHTSA conduct its own R&R study and
harmonize tools with IIHS if possible. GM also presented results from a
limited study of gauge repeatability with the proposed tools during a
November 23, 2015, ex parte meeting.\45\ GM explained that the gauge
repeatability study showed that further refinement of the proposed
tools was required to meet industry guidelines of repeatability.
---------------------------------------------------------------------------
\44\ Ex parte memo for September 22, 2015, meeting with FCA. See
docket NHTSA-2014-0123-0052 and NHTSA-2014-0123-0053 in
<a href="http://www.regulations.gov">www.regulations.gov</a>.
\45\ Ex parte memo for November 23, 2015, meeting with GM. See
docket NHTSA-2014-0123-0056 in <a href="http://www.regulations.gov/">www.regulations.gov/</a>.
---------------------------------------------------------------------------
b. Post-NPRM Research
After careful consideration of comments received in response to the
NPRM, NHTSA carried out a study to assess whether and how the tools
proposed in the NPRM could be modified. Specifically, some commenters
expressed concerns about the R&R of the tools and the subjectivity of
some measurements. Some commenters suggested improvements to the tools
and the tools' instrumentation to have more repeatable measurements and
better usability. Finally, some commenters also stated that NHTSA
should harmonize or adopt the tools and procedures being used by the
IIHS for consistency of evaluation on the lower anchorage
attachments.\46\
---------------------------------------------------------------------------
\46\ In June 2015, IIHS released its rating protocol along with
tools to assess the usability of the lower anchorages with similar
requirements.
---------------------------------------------------------------------------
During the course of the study, NHTSA reviewed IIHS's rating
protocols and tools to consider any beneficial features provided by the
tools. NHTSA proceeded to implement tool improvements to address the
commenters concerns by updating the AFT and its instrumentation via an
iterative process.\47\ Specifically, NHTSA added features to the AFT,
similar to the IIHS rating protocol,\48\ by including a guide rod to
guide the tool towards the anchorage. Other modifications included
updating instrumentation to digitally record the angle during the test,
adding an actuator allowing for a steady rate of force application, and
adding a support leg to stabilize the tool and maintain the approach
angle during the attachment force measurements. These modifications
were expected to produce more consistent results by resolving the issue
of aligning the tool with hidden anchorages, reducing the
inconsistencies from off-axis loading and having more consistent
readings with new instrumentation. The repeatability study results are
discussed in greater detail in the GR&R Study portion of this section
below.
---------------------------------------------------------------------------
\47\ Detailed documentation of these changes can be found in the
technical report: Louden, A.E., Wietholter, K., & Pruitt, C.E.
(2022, May). Evaluation of LATCH Usability Tools Update (Report No.
DOT HS 813 229). National Highway Traffic Safety Administration.
This report will be available in this final rule's docket.
\48\ IIHS developed a tool that included a depth measurement
gauge within the AFT.
---------------------------------------------------------------------------
For the updated CAT, NHTSA added a pulley bridge (with adjustable
feet to make it level) to apply a 67 N (15 lbf) force vertically to
remove the difficulty of applying the constant load manually. NHTSA
also added digital instrumentation that allowed time-history data to be
recorded. Further, NHTSA replaced the rotary potentiometer several
commenters expressed concerns about with an analog position sensor to
collect the angle data more reliably. To improve durability, the jaw of
the tool was also reinforced with steel plates and the latch tooth was
updated to be refabricated completely out of steel.
For the depth measurement \49\ NHTSA modified the ADT through the
addition of a sliding view bar to create a more consistent view angle
and an additional depth gauge measurement device to provide a numerical
value for the depth, rather than using color markings for the 20 mm
depth reading.
---------------------------------------------------------------------------
\49\ NHTSA evaluated the IIHS depth tool method that is embedded
in IIHS's attachment force tool; however, results showed that the
readings using this tool were different from the proposed tool, so
NHTSA did not continue to use IIHS's tool for depth measurements.
Details can be found in the report: Louden, A.E., Wietholter, K., &
Pruitt, C.E. (2022, May). Evaluation of LATCH Usability Tools Update
(Report No. DOT HS 813 229). National Highway Traffic Safety
Administration. This report will be available in this final rule's
docket.
---------------------------------------------------------------------------
GR&R Study
Following its initial study and tool modifications, NHTSA
considered comments expressing concerns over tool repeatability and
reproducibility. In response to comments that NHTSA should use the
industry's standard gauge repeatability and reproducibility (GR&R)
methodology to evaluate the measurement tools' R&R, NHTSA conducted a
GR&R study with the improved tools to determine if the updated tools
provided repeatable and reproducible measurements.
NHTSA contracted UMTRI to evaluate the NHTSA-improved tools. The
evaluation sought to identify any further improvements that could be
made to the tools and to do a GR&R assessment study with the modified
tools. NHTSA also required UMTRI to perform a statistical analysis to
quantify the usability of the toolsets according to industry standards
to address manufacturers' NPRM comments.\50\
---------------------------------------------------------------------------
\50\ Klinich, K.D., Manary, M.A., Boyle, K., Malik, L., Bowman,
P., Flannagan, C.A., ``Evaluation of Repeatability and
Reproducibility of Proposed Tools to Assess Lower Anchor Usability''
UMTRI-2018-4, July 2018. This report will be docketed with the final
rule.
---------------------------------------------------------------------------
UMTRI conducted the GR&R study in two phases to evaluate the
effects of different operators, tools, and vehicles. Each phase used 10
different vehicle models for the modified tool evaluations. UMTRI
picked the first phase's vehicles based on the 214 vehicles used for
the IIHS CRAS study. Phase one vehicles were selected to allow
evaluation of the tools and procedures across a range of different seat
styles found in the MY 2016 vehicle fleet.\51\ For phase two, UMTRI
again based vehicle selection on the IIHS CRAS study vehicles, with an
emphasis on finding vehicles with lower anchorages in the second-row
center (2C) seating position or vehicles with a third row of seats.
UMTRI also looked at the data from phase one to identify
[[Page 1300]]
measures of interest for phase two, such as pick-up trucks and coupe
vehicles. In selecting vehicles for the study, UMTRI tried to maximize
variation among manufacturers, while also considering the availability
to rent such vehicles for testing. UMTRI's GR&R study \52\ found that
for the clearance angle measurement 92 percent of variance is
attributable to the vehicle (part) variability and only 8.4 percent is
attributable to system variability (combined variability of the tools,
operator, and repeat measurements). For the depth measurement UMTRI
found that 93 percent of the variance is attributed to the vehicle
(part) variability and only 7 percent to the system variability. For
the force measurement, UMTRI found that 67 percent of the variance
comes from vehicle (part) variation and 33 percent comes from the
system variability. According to the Measurement Systems Analysis
Reference Manual (MSA),\53\ a system variation in the measurement of 10
percent or less is considered acceptable R&R of the measurement, while
a system measurement variability of 30 percent or more is considered
unacceptable. The results of UMTRI's GR&R Study demonstrate that the
anchorage depth and clearance angle measurements obtained via the
updated ADT and CAT have good R&R, but that the anchorage force
measurement with the AFT V2 does not. Further details of the GR&R
analysis are available in the UMTRI GR&R study report.\54\
---------------------------------------------------------------------------
\51\ This analysis is available in the technical report:
Klinich, K.D., Manary, M.A., Boyle, K., Malik, L., Bowman, P.,
Flannagan, C.A., ``Evaluation of Repeatability and Reproducibility
of Proposed Tools to Assess Lower Anchor Usability'' UMTRI-2018-4,
July 2018.
\52\ For details on the vehicles and measurements see Klinich et
al (2018).
\53\ This reference manual, developed by the vehicle industry,
contains guidelines for assessing the quality of a measurement
system. Down, M., Czubak, F., Gruska, G., Stahley, S., Benham, D.
(2010) Measurement Systems Analysis Reference Manual, Fourth
Edition. Chrysler Group LLC, Ford Motor Company, General Motors
Corporation. <a href="http://www.rubymetrology.com/add_help_doc/MSA_Reference_Manual_4th_Edition.pdf">http://www.rubymetrology.com/add_help_doc/MSA_Reference_Manual_4th_Edition.pdf</a>.
\54\ Klinich et.al. 2018.
---------------------------------------------------------------------------
c. Summary of Decision on Assessing Usability of Lower Anchorages
This final rule adopts the updated lower anchorage depth and
clearance angle tools and requirements, but not the attachment force
requirement. These adopted requirements will ensure that lower
anchorages on vehicles subject to this rule have sufficient clearance
around each lower anchorage, and that the lower anchorages are within
25 mm of the outer surface of the seat bight (anchorage depth).\55\
Lower anchorages meeting these requirements will be easier to use, as
shown by the UMTRI and IIHS data.
---------------------------------------------------------------------------
\55\ See Anchorage Depth Tool Decision below (section V.d.2),
where NHTSA explains why the anchorage depth threshold changed from
20 mm to 25 mm.
---------------------------------------------------------------------------
The LATCH Usability study found these ease-of-use specifications
correlate with correct child restraint installations. National Child
Restraint Use Special Study (NCRUSS) \56\ data showed that a loose CRS
installation comprises one of the five most significant mistakes
consumers make when installing child restraints. Loose CRS
installations can result in greater movement of a child and their CRS
during a crash, increasing the risk for injury and higher injury
severity due to possible contact with vehicle interior structures.
CRASs designed to be easier to properly use will increase correct
(tight) CRS installations, making children safer in a crash.
---------------------------------------------------------------------------
\56\ Greenwell, N.K. (2015, May). Results of the national child
restraint use special study. (Report No. DOT HS 812 142).
Washington, DC: National Highway Traffic Safety Administration.
---------------------------------------------------------------------------
The NPRM proposed clearance angle, attachment force, and anchorage
depth specifications. This final rule is only adopting requirements and
measurement tools for the clearance angle and anchorage depth. The
agency evaluated a series of changes to the attachment force tool to
improve its R&R. However, the GR&R \57\ study found that measurements
from the attachment force tool lacked acceptable level of R&R needed
for adopting into the standard.\58\ NHTSA does not believe further
improvements to the attachment force tool will be enough to achieve a
sufficient R&R.
---------------------------------------------------------------------------
\57\ GR&R is the process used to evaluate a gauging instrument's
accuracy by ensuring its measurements are repeatable and
reproducible. The process includes taking a series of measurements
to certify that the output is the same value as the input, and that
the same measurements are obtained under the same operating
conditions over a set duration. See <a href="https://asq.org/quality-resources/gage-repeatability">https://asq.org/quality-resources/gage-repeatability</a>.
\58\ Klinich, K., Manary, M.A., Boyle, K., Malik L.J., Bowman,
P., Flannagan, C.A.'' Evaluation of Repeatability and
Reproducibility of Proposed Tools to Assess Lower Anchor Usability''
July 2018. Report will be docketed with this final rule.
---------------------------------------------------------------------------
UMTRI's LATCH Usability study \59\ identified three vehicle
hardware characteristics serving as predictors for correct CRS use,
analyzing the predicting factors of force and depth separately and
together. Depth and attachment force when analyzed separately showed
each were highly significant predictors of correct lower anchors use.
But when these vehicle characteristics were analyzed together, force
became marginally significant while depth remained a highly significant
predictor. UMTRI concluded that while these results do not guarantee a
causal relationship between depth and correct installations, the
results do indicate that depth is a better predictor of correct
installations than force.
---------------------------------------------------------------------------
\59\ Klinich et al., ``LATCH Usability in Vehicles,'' UMTRI-
2012-7, April 2012. Link: <a href="https://deepblue.lib.umich.edu/handle/2027.42/90856">https://deepblue.lib.umich.edu/handle/2027.42/90856</a>.
---------------------------------------------------------------------------
Although Alliance and FCA commented that only the anchorage depth
requirement was warranted, NHTSA disagrees. UMTRI's LATCH Usability in
Vehicles Study analyzed depth and clearance angle. Study results
concluded that separately they each were highly significant predictors
of correct use of lower anchors. When analyzed together, to the extent
there is unique variance attributable to depth and clearance
separately, depth and clearance angle both became marginally
significant. This indicates that both are equally predictive of correct
installation.
Because the study could not estimate the contribution of each
feature, NHTSA cannot accurately calculate the effect of not having the
attachment force as a requirement. The data does indicate that by
having clearance angle and depth requirements, correct CRS usage will
improve.
d. Detailed Agency Decisions Regarding the Tools and Performance
Criteria
1. Clearance Angle Tool and Minimum Allowable Clearance Angle
NHTSA understands that some vehicles will need redesign to meet
both requirements. But as presented in figure 9 of the 2015 NPRM,\60\
the depth requirement is feasible in many vehicles without making any
design changes to meet the S9.2.2(b) requirements. Following careful
consideration of comments received and further studies described above,
NHTSA has modified the NPRM's proposed clearance angle tool (CAT) to
address several concerns raised by commenters. The final design of the
CAT now includes a pulley bridge to apply a consistent vertical force
of 67 N (15 lb) to address commenters' concerns regarding the
difficulty in applying the force in the proposed CAT. Further, although
the proposed CAT had digital instrumentation allowing for the recording
of time-history data, based on comment feedback, NHTSA has implemented
new instrumentation to improve measurement repeatability, including an
analog position sensor and an Interface S-Type load cell.
---------------------------------------------------------------------------
\60\ See <a href="http://www.regulations.gov/document/NHTSA-2014-0123-0001">www.regulations.gov/document/NHTSA-2014-0123-0001</a>.
---------------------------------------------------------------------------
UMTRI's GR&R study found that the measurement variability of the
updated CAT \61\ system was less than 10 percent of the total
measurement variability, confirming that the updated CAT
[[Page 1301]]
measurements have sufficient R&R for regulatory purposes.
---------------------------------------------------------------------------
\61\ Identified as CAT V2 in technical reports.
---------------------------------------------------------------------------
Accordingly, this final rule incorporates the requirement of a
minimum of 54-degrees clearance angle in FMVSS No. 225 when applying a
67 N vertical load to the updated tool. Drawings of the final updated
CAT design have been incorporated by reference into FMVSS No. 225.
NHTSA has placed a copy of the drawings in the docket for this final
rule.
While supportive of a clearance angle requirement, Advocates argued
that the proposed 54 degree minimum was too low. NHTSA selected the 54-
degree clearance angle based on a 50 percent correct CRS use in UMTRI's
LATCH Usability study. Only 2 of the 98 vehicles studied by UMTRI had a
clearance angle above 75 degrees, which calls into question the
feasibility of defining 75 degrees as a limit. The proposed values
provide an improvement on correct installations and are not overly
burdensome for manufacturers to meet. NHTSA also believes that vehicles
will be well above the 54 degree clearance angle, as the standard will
also require anchorages depths that typically result in higher
clearance angles. Fifty-four of the 98 vehicles in UMTRI's study had
clearance angles over 54 degrees (ranging 54-83 degrees), which will
improve correct installations beyond the 50 percent used to establish
the threshold.
In response to the Alliance's request for clarification on whether
the CAT measurements must be made independently or at both anchorages
concurrently, the CAT measurements are to be done independently at each
lower anchorage in the vehicle. Further, NHTSA does not agree with the
Alliance's suggestion that the weight of the tool needs to be
subtracted from the total force applied to arrive at the 67 N
requirements. With the tool modifications to the CAT, the 67 N will
provide a constant load, and subtracting the force due to the weight of
the tool would add unnecessary complexity to the system.
NHTSA acknowledges comments made by MGA \62\ on the proposed tools
and technical drawings published with the NPRM. Specifically, MGA
stated that ``the spring pockets are 0.146'' offset, which causes the
spring to fall out during compression.'' Based on this, MGA stated that
it did the following: (1.) moved the pivot to spring pocket distance as
follows: 4.970-2.500 = 2.470 (upper spring pocket); (2.) moved the
pivot to spring pocket distance as follows: 3.216-0.600 = 2.616 (lower
spring pocket); (3.) moved the upper spring pocket forward 0.125'' to
align the upper and lower spring pocket more closely, and prevent the
spring from falling out during compression.
---------------------------------------------------------------------------
\62\ For full comments and associated figures see
<a href="http://www.regulations.gov/comment/NHTSA-2014-0123-0049">www.regulations.gov/comment/NHTSA-2014-0123-0049</a>.
---------------------------------------------------------------------------
In addition to these changes, MGA pointed out that the load cell
presented in NHTSA's NPRM is not commercially available. As such, MGA
replaced the load cell with an Interface SSM-AJ-100 load cell. MGA
explained the hardware to attach the load cell to the handle and ball
and joint connection are Interface CLV-104 clevises. MGA also noted the
female rod end is McMaster part number 60645K32, while the male rod end
is unchanged. Finally, MGA redefined the clearance angle tool handle
measurements to fit the Interface clevis CLV-104 that is used with the
Interface SSM-AJ-100 load cell.
In response to these comments, NHTSA has updated the drawings as
follows: the dimension 4.97 inches in drawing DA609-001 (figure 9 in
MGA comments) is corrected to 5.15 inches to eliminate the offset this
dimension created with drawing DA609-003. However, NHTSA did not move
the upper spring pocket forward 0.125 inches as suggested by MGA
because the spring was modified to a conical spring (in Drawing DA609-
000), which prevents the spring from falling out during compression.
The upper spring pocket was thus left in the same location as proposed.
In response to comments on the load cell, NHTSA updated the drawings as
follows for this final rule: the proposed load cell is changed to the
S-Type load cell suggested by MGA, which is commercially available.
However, suggested changes to the handle and attachments to the handle
will not be implemented, as they are now moot as this part was removed
and replaced with a pulley system.
Finally, NHTSA acknowledges MGA's request for clarification on
certain inconsistent dimensions in two drawings, as seen in figures 17
and 18 of MGA's comments.\63\ In response to these comments, this final
rule updates the drawings as follows: the material in Drawing DA609-005
is changed from having a material PL 1'' x 1\3/16\'' x 1\7/8\'' to PL
1'' x 1\3/16\'' x 5'' to correct the inconsistent dimensions in the
drawing. Further, drawing DA609-006 is removed as the mount in this
drawing is no longer needed.
---------------------------------------------------------------------------
\63\ Docket No. NHTSA-2014-0123-0049.
---------------------------------------------------------------------------
2. Anchorage Depth Tool and Maximum Allowable Anchorage Depth
NHTSA acknowledges that several commenters, including GM and FCA,
expressed concerns about the repeatability of the ADT tool and the
subjectivity of the viewing angle in determining whether the
measurement was 20 mm or less. After careful consideration this final
rule's updated ADT \64\ addresses concerns over viewing angle
subjectivity through the addition of a view bar and zero-strip that
translate the viewing angle into a physical measurement. In support of
this decision, UMTRI's GR&R study found that the ADT measurement
variability of the updated system was less than 10 percent of the total
measurement variability (specifically, 93 percent of the variance in
the depth measurements is attributed to vehicle variation and only 7
percent to the system variability), confirming that the updated ADT
measurements have sufficient R&R for regulatory purpose.
---------------------------------------------------------------------------
\64\ Identified as ADT V4 in technical reports.
---------------------------------------------------------------------------
This final rule is also increasing the NPRM's proposed 20 mm limit
to 25 mm. As noted earlier, since the study vehicles were selected
based on their different characteristics and not as a randomized
selection, the agency's analysis does not fully evaluate the
variability across vehicles. There could be some anchorage depth
measurement variability in some seat designs. Further, the GR&R study
by UMTRI considered depth measurements rounded to the nearest quarter
cm. In acknowledgment of these limitations in the GR&R analysis, NHTSA
is specifying that the anchorage depth be 25 mm or less, rather than
the 20 mm proposed in the NPRM. As such, measurement by the finalized
ADT will account for measurement and manufacturing variability.
Expanding the depth requirement to 25 mm will still result in improved
usability and a higher number of correct installations.\65\
---------------------------------------------------------------------------
\65\ UMTRI's LATCH Usability study (2012) was not conducted with
the precision tools such as the ADT included in this final rule. The
UMTRI Study tools had some ambiguities regarding a consistent
viewing angle to detect the change in color from the hook-type tool.
The additional 5 mm is in the realm of depth reading variability
from that study.
---------------------------------------------------------------------------
NHTSA did not consider lowering the anchorage depth to less than 20
mm, which would be a more stringent threshold than that proposed in the
NPRM. In response to the Alliance's comment asking why a 4 cm anchorage
depth was not proposed, as that depth also showed correct installations
in UMTRI's LATCH Usability study, NHTSA points out that the UMTRI LATCH
Usability study found that study
[[Page 1302]]
volunteers correctly installed CRSs 50.7 percent of the time when using
anchorages with depths 2 to 4 cm,\66\ but that anchorage depths of 0 to
2 cm showed a more pronounced improvement to 85.9 percent correct CRS
installation. As a 35 percent increase in the number of correct CRSs
installed is a significant increase in the crash safety protections
provided to young children, the Agency declines to consider a 4 cm
anchorage depth for this final rule. In response to the Alliance's
suggestion to better define the tensioning and angle placement of the
ADT during the procedure, as the updated ADT is pulled taut so that the
anchorage bar engages the tool, a need to define the tension does not
exist, as the required tool is rigid.
---------------------------------------------------------------------------
\66\ The UMTRI ``LATCH Usability'' study showed correct use of
85.9 percent, 50.7 percent and 43.1 percent for lower anchorage
depths of 0-2 cm, 2-4 cm and 4-6cm respectively. We expect lower
anchorages with depths between 2-4 cm that are closer to 2 cm would
have higher correct use and those closer to 4 cm would have lower
correct use.
---------------------------------------------------------------------------
NHTSA is rejecting a comment requesting the removal of the
prohibition in FMVSS No. 225 on stowable lower anchorage bars, as lower
anchorages should be readily available for use and no further steps
should be necessary (other than removing a lower anchorage specific
cover) to access and use them.
NHTSA agrees with GM's recommendation to position the ADT at an
angle parallel to the seat cushion to make measurements and has revised
the NPRM's proposed procedure to specify that the ADT will be
positioned at an angle parallel to the seat cushion. The test procedure
will indicate how to measure the seat cushion angle (using a 2 ft level
and an inclinometer) and how to position the ADT to reach this angle
(use of shims if necessary). In response to expressed concerns over the
measuring tool potentially displacing the trim covering or surrounding
trim being displaced by the tool, NHTSA notes that this final rule's
anchorage depth measurement procedure allows for clear depth
measurement via the taping away from anchorages (with masking tape)
such things as coverings, flaps, or other vehicle parts. In relation to
concern over trim coverings, including slits where the fabric or
leather is too stiff to be taped, there should be minimal manipulation
of the slit to introduce and hook the ADT in the anchorage and pull it
back. The ADT may push away some of the fabric or leather when it is
engaged to the lower anchorage. The depth will be measured where the
viewing strip comes in contact with the vehicle seat (which includes
the fabric or leather). Since the vehicle is prepared before the test
measurement by marking the vehicle seat with a line perpendicular to
the anchorage center, the tool can be easily directed to the anchorage.
In response to commenters that suggested developing a depth measure
based on a hard point given the difficulty in designing and controlling
the variance of the foam/trim elements during the design process, NHTSA
respectfully disagrees with this suggestion. The LATCH Usability study
\67\ found that anchorages positioned less than 20 mm from the seat
bight result in more correct installations. Further, one noted issue
consumers experience when installing CRSs with deep anchorages is
difficulties with the foam of the seat and/or the fabric/leather
surrounding the anchorage. As anchor depth measurement from a hard
point measurement does not take the interactions of the seat foam and
fabric into consideration, a depth measurement based on a seat hard
point would not necessarily improve ease-of-use and correct
installations. NHTSA does acknowledge that there may be greater
variability in foam and different trim levels than those considered in
the UMTRI GR&R analysis. To account for any potential measurement or
manufacturing variability this final rule specifies an anchorage depth
of no more than 25 mm, as opposed to the proposed 20 mm, to account for
measurement and manufacturing variability.
---------------------------------------------------------------------------
\67\ Klinich et al., ``LATCH Usability in Vehicles,'' UMTRI-
2012-7, April 2012. Link: <a href="https://deepblue.lib.umich.edu/handle/2027.42/90856">https://deepblue.lib.umich.edu/handle/2027.42/90856</a>.
---------------------------------------------------------------------------
Several commenters expressed concerns over the costs of required
tooling changes to meet the depth requirements of this final rule.
NHTSA acknowledges that tooling changes for existing production
vehicles can be very costly and are better accommodated during the
early design stage of a vehicle's renewal cycle to minimize any
potential costs. Accordingly, the agency finds good cause to provide
more lead time and a phase-in for manufacturers to account for
different trims and the possibility of tooling changes to meet the
depth requirements required by this final rule. As such, this final
rule is providing a longer lead time than that proposed in the NPRM,
with a phase-in schedule (see Lead Time Section). NHTSA is permitting
optional early compliance with this final rule's requirements.
3. Attachment Force Tool
Following careful consideration of comments received and additional
testing, NHTSA has decided not to adopt the NPRM's proposed attachment
force requirements into FMVSS No. 225. Following publication of the
NPRM, NHTSA attempted to improve the R&R of the AFT. However, UMTRI's
GR&R study, which used the improved AFT, found that 67 percent of depth
measurement variance came from vehicle (part) variation and 33 percent
came from system variability (variability attributed to the tools,
operators, and repeated measurements). The Measurement Systems Analysis
Reference Manual (MSA) \68\ document, followed by the vehicle industry,
indicates that when evaluating a test procedure, it is acceptable if
the system's percentage variation is less than 10%. This means the
improved AFT failed to reach an acceptable R&R for adoption into the
standard. NHTSA does not believe further improvements to the AFT would
achieve sufficient repeatable and reproducible measurements for
regulatory purposes. Further, although Ford suggested using the average
of several measurement trials using the AFT as the criteria for
anchorage attachment force, NHTSA found R&R was not sufficiently
improved by considering the average of five measurement trials for some
vehicle seats. As NHTSA has determined the adoption of the AFT into
FMVSS No. 225 is not feasible, this final rule does not address
additional comments received suggesting improvements to the tool.
---------------------------------------------------------------------------
\68\ Down M, Czubak F, Gruska G, Stahley S, Benham D. (2010)
Measurement Systems Analysis Reference Manual, Fourth Edition.
Chrysler Group LLC, Ford Motor Company, General Motors Corporation.
Link: <a href="http://www.rubymetrology.com/add_help_doc/MSA_Reference_Manual_4th_Edition.pdf">http://www.rubymetrology.com/add_help_doc/MSA_Reference_Manual_4th_Edition.pdf</a>.
---------------------------------------------------------------------------
Despite the decision not to include an attachment force criterion
into FMVSS No. 225, the remaining requirements of this final rule will
improve the ease-of-use of the lower anchorages. UMTRI's study \69\
identified the characteristics of attachment force, clearance angle,
and attachment depth as predictors for correct CRS use, and then
modeled the predicting factors of force and depth both separately and
together. Analyzed separately, depth and attachment force were highly
significant predictors of the correct use of lower anchors. Analyzed
together, depth remained a highly significant predictor, while
attachment force was only a marginally significant
[[Page 1303]]
predictor. As such, UMTRI concluded that although these results do not
guarantee a causal relationship between depth and correct
installations, they do indicate that depth is a somewhat better
predictor of correct CRS installations than attachment force. This
final rule's depth requirements ensure that the lower anchorages will
be placed in a more forward position, making them more likely to avoid
foam material and structures and potentially resulting in decreased
force needed to attach the lower anchorage. Further, this final rule's
required clearance angle will ensure no material or structure will
prevent placement of the lower anchorage attachment, which may also
result in less required force to attach the lower anchorage.
---------------------------------------------------------------------------
\69\ Klinich et al., ``LATCH Usability in Vehicles,'' UMTRI-
2012-7, April 2012. Link: <a href="https://deepblue.lib.umich.edu/handle/2027.42/90856">https://deepblue.lib.umich.edu/handle/2027.42/90856</a>.
---------------------------------------------------------------------------
VI. Improving the Ease of Using the Tether Anchorage
FMVSS No. 225 currently requires vehicle manufacturers to equip
vehicles with a tether anchorage at three rear designated seating
positions (two of these positions are also required to be equipped with
lower anchorages). Tether anchorages must be in a specified zone
accessible without the need for any tools other than a screwdriver or
coin. Tether anchorages must be easy to use, as they are the primary
factor behind the estimated 36-50 lives saved a year following NHTSA's
adoption of FMVSS No. 225.\70\
---------------------------------------------------------------------------
\70\ 64 FR 10786.
---------------------------------------------------------------------------
To further improve the usability of the tether anchorage by making
it easier for customers to recognize and access, the NPRM proposed the
following requirements:
<bullet> Reduce the zone in which a tether anchorage must be
located to prevent tether anchorages from being placed deep under a
vehicle seat.
<bullet> As some tether anchorages are too close to a structure,
such as a head restraint, specify a minimum 165 mm (6.5 in) distance
from a specified reference point on the vehicle seat to the tether
anchorage to allow for the tightening of the tether strap. This
requirement will ensure that adequate clearance is provided to tighten
the tether strap.\71\
---------------------------------------------------------------------------
\71\ The NPRM also proposed amending FMVSS No. 213 to limit the
length of the CRS tether hardware assembly (which consists of a
tether hook and hardware to tighten and loosen the tether strap) to
165 mm (6.5 in) so that the tightening mechanism can be easily used
in the clearance space around a tether anchorage.
---------------------------------------------------------------------------
<bullet> Tether anchorages must be accessible without the need for
any tools other than a screwdriver or coin, and without folding the
seatback or removing carpet or other vehicle components. The tether
anchorage could be covered with a cap, flap, or cover, provided that
the cap, flap, or cover is specifically designed to be opened, moved
aside, or to otherwise give access to the anchorage without the use of
any tools and is labeled with a specific symbol indicting the presence
of the tether anchorage underneath.
<bullet> Requiring a standardized rigid bar so consumers could more
easily recognize and find it, as currently some tether anchorages are
made from flexible webbing.
<bullet> Standardizing the tether anchorage marking by requiring
that it match a marking on the child restraint system tether and be
placed within a specified distance from the anchorage.
General Comments
Commenters almost unanimously supported improving the ease-of-use
of tether anchorages but differed in their views on specific NPRM
proposals. Overall, child restraint manufacturers and private
individuals supported the proposed improvements to the ease-of-use of
the tether anchorage. SRN and an individual, Dr. Baer,\72\ agreed on
the standardization, accessibility, and clearance (165 mm distance to
tether anchor) proposals to improve tether use. However, Dr. Baer
disagreed with allowing tether anchorage covers, stating that they hide
a safety feature. SRN and Dr. Baer expressed concerns over some tether
anchorage designs concealed by other vehicle structures, making them
difficult to access. IIHS also supported reducing the allowable zone
for tether anchorages to better align allowable locations with the
locations parents expect to find tether anchorages. Safe Kids \73\
expressed support for a harmonized, consistent, and easily understood
way to identify and use the CRAS.
---------------------------------------------------------------------------
\72\ Dr. Baer is a pediatrician, advocate and nationally
certified child passenger safety instructor best known as The Car
Seat Lady.
\73\ Safe Kids is a network of organizations working to prevent
unintentional childhood injury, the leading cause of death and
disability for children ages 1 to 14.
---------------------------------------------------------------------------
In contrast, the Alliance and several vehicle manufacturers
objected to the proposed requirements to reduce the zone where top
tethers could be located, including specifically to the proposed tether
anchorage location on the package shelf \74\ behind second-row seats in
vehicles such as sedans. The Alliance stated that many passenger cars
that have the tether anchorages conveniently located in the package
shelf behind the seat will not meet the proposed 165 mm minimum wrap
around distance. The Alliance explained that current design locations
that would be precluded by the proposed requirements do, in fact,
enable effective attachment since the path over a fixed head restraint
or under an adjustable head restraint provides additional wraparound
distance to tighten the tether strap. Several vehicle manufacturers
stated that the proposed requirement would force the relocation of
tether anchorages rearward in the vehicle, resulting in less hand
clearance to the vehicle backlight \75\ window for manipulating the
tether hook. Vehicle manufacturers also expressed concern over costly
repackaging of components such as speaker assemblies that currently
occupy the space where the tether anchorage would have to be placed.
Some commenters urged NHTSA to use a point farther forward in the
vehicle's seat than the proposed SB point, explaining the SB point is
not a reference that can be found on all of their vehicles.
---------------------------------------------------------------------------
\74\ The shelf behind the rear seat in a sedan.
\75\ Backlight is the rear windshield or back window glass in a
vehicle.
---------------------------------------------------------------------------
The Alliance and several vehicle manufacturers sought clarification
on some terms related to the reduced tether anchorage zone under the
seat, and also commented on other proposed provisions for improving the
ease-of-use of tether anchorages (e.g., accessing tether anchorages
without tools, accessing tether anchorages without folding the seatback
or removing carpet or other vehicle components, such as luggage
compartment security covers, and using rigid bars in light trucks).
Commenters also expressed concerns with the proposed requirements based
on their implications and costs. Vehicle manufacturers generally
commented that the proposed 3-year lead time is insufficient to account
for necessary changes, and many asked for a phase-in of the
requirements.
a. Attaching to the Tether Anchorage
Tether Anchorage Accessibility--Zone Under the Seat
To promote accessible tether anchorages, current FMVSS No. 225
requires that tether anchorages be located within the shaded zone shown
in figures 3 through 7 of FMVSS No. 225 for the designated seating
position (DSP) where the anchorage is installed. In considering changes
to FMVSS No. 225 to further increase tether anchorage accessibility,
the agency first evaluated vehicle fleet data to better understand
where tether anchorages are currently located. The evaluation found
that the most common tether anchorage
[[Page 1304]]
locations are the seatback (41 percent), the package shelf (37
percent), the back wall of the occupant compartment (8 percent), the
roof (6 percent), the floor (4 percent), and under the seat (3
percent). NHTSA contemplated the merits of designing the NPRM to
considerably limit the zones in figures 3 through 7, but decided
against this approach following review of NHTSA's test data. This data
showed that the current allowable locations of tether anchorages do not
increase the risk of injuries, as their performance and loading to the
anchorages are very similar to tether anchorages that are centered and
closer to the seat. Further, NHTSA acknowledges that vehicle
manufacturers must consider many factors in deciding where to place a
tether anchorage, including the strength of the structure to which the
tether anchorage is affixed, the degree to which the tether anchorage--
or the child restraint, when using the anchorage--interferes with
ingress, egress, seating, and/or the comfort and safety of vehicle
occupants. Due to these considerations, vehicle manufacturers sometimes
install tether anchorages slightly off-center to a seating position, or
on the roof, floor, or back wall. Recognizing there is merit in
providing flexibility to manufacturers to balance where to locate the
anchorages, the agency decided not to considerably narrow the zones in
figures 3 through 7.\76\ Instead, the NPRM sought to improve the ease
of using tether anchorages via other means.
---------------------------------------------------------------------------
\76\ IIHS was the sole commenter that encouraged NHTSA to
further reduce the allowable zone for tether anchorages to better
align allowable locations with where parents expect to find tether
anchorages. While NHTSA agrees a more reduced zone would place
tether anchorages where consumers may be more likely to anticipate
them, the agency must also consider other factors a vehicle
manufacturer has to weigh when deciding the location of tether
anchorages. Manufacturers consider factors such as strength of the
structures, features that the manufacturer may design into seats
such as pass through openings, seat back folding mechanisms that may
cause the tether anchorages to be in the back of the seat, and other
design considerations. Thus, NHTSA is not reducing the zones in this
rulemaking.
---------------------------------------------------------------------------
First, the agency proposed to reduce the allowable zone under the
seat, because the shaded zone shown in figures 3 through 7 encompasses
a wide area that has resulted in some tether anchorages being located
where consumers have had difficulty accessing them, such as deep under
the seat where folding the seat is required to reach/attach the tether
anchorage.\77\ As such, NHTSA proposed to amend figures 3 through 7 in
the standard to disallow tether anchorages from being placed deep under
the seat. Specifically, the agency proposed that the forwardmost edge
of the allowable tether anchorage zone represented by the shaded area
in figure 3 of the standard be moved rearward to a position defined by
the intersection of the vehicle floor with a plane parallel to the
torso line reference plane passing through the rearmost point of the
bottom of the seat at its centerline.\78\
---------------------------------------------------------------------------
\77\ This deep under the seat location is the forward-most edge
of the area under the vehicle seat. The location is defined by the
intersection of the torso line reference plane (defined by the 2016
SAE J826 two-dimensional drafting template) and the floor pan.
\78\ Vehicles with tether anchorages located deep under the seat
where the seat must be folded to reach the anchorages are no longer
manufactured, so this change in requirements will have little or no
impact on current vehicle designs. However, the amendment is needed
to prevent these designs from coming back into the fleet.
---------------------------------------------------------------------------
Comments Received
Vehicle manufacturers generally disagreed with the proposal laid
out in the NPRM. Global stated that for certain vehicle designs the
bottom of the seat may be the most suitable location for the anchorages
and requested that the agency permit continued use of the bottom of the
seat for tether anchorages if the manufacturer includes appropriate
markings on the seatback to alert consumers to the anchorage location.
The Alliance argued the proposal to restrict the allowable tether zone
under the seat may be appropriate for passenger cars with limited space
under the seat, but it unnecessarily limits the location of the
anchorage for mini-vans, vans and some SUVs. The Alliance provided
figures in its comments \79\ showing a full-size van rear seat with the
upper tether anchorage located on the seat structure forward of the
forward-most limit of the proposed zone and explained that the location
provides a readily accessible upper anchorage point formed into the
seat. The Alliance stated the proposed acceptable zone would require
additional anchorage hardware that would need to be welded to the seat
structure. The Alliance explained that because the current design is
stamped into the existing seat structure, manufacturers can voluntarily
provide additional anchorages at very low cost (i.e., the 10-seat
version of this full-size van has eight tether anchorages available for
use). The Alliance opined that there is no need to revise the zone such
that these tether anchorages would no longer be permitted, given the
easy access and visibility of tether anchorages.
---------------------------------------------------------------------------
\79\ Figure 3 of Docket No. NHTSA-2014-0123-0027.
---------------------------------------------------------------------------
Similarly, Ford commented that the proposal to limit the tether
anchorage location using a plane that is parallel to the torso line
that passes through the ``rearmost point of the bottom of the seat'' is
overly restrictive for some free-standing seats (i.e., SUVs and vans).
Ford suggested basing the forward-most limit of the acceptable zone on
the SgRP. Ford proposed using a vertical plane 120 mm rearward of the
SgRP as the forward limit of the acceptable zone, which would remove
the ambiguity regarding the ``rearmost point of the bottom of the
seat'' and, combined with labeling, permit some currently existing
under-seat designs that do not have accessibility issues. Ford added
that the plane is already specified in the standard to define the
forward-most limit of the lower anchorage acceptable zone. Ford
included three illustrations \80\ depicting the current allowable
under-seat zone, the allowable zone proposed in the NPRM, and a
modified proposal that would limit the anchorage location to the plane
120 mm rear of the SgRP.
---------------------------------------------------------------------------
\80\ Ford's illustrations can be found in figure 3 of Docket No.
NHTSA-2014-0123-0026.
---------------------------------------------------------------------------
The Alliance and Honda requested clarification on how to define the
intersection of the vehicle floor with a plane parallel to the torso
line reference plane passing through the rear-most point of the bottom
of the seat at the centerline of the seat. Both the Alliance \81\ and
Honda \82\ presented illustrations of different scenarios where they
indicated the rearmost point of the bottom seat was unclear and
requested clarification.
---------------------------------------------------------------------------
\81\ Alliance's illustrations can be found on pages 8-9 of
Docket No. NHTSA2014-0123-0027.
\82\ Honda's illustrations can be found on pages 3 of Docket No.
NHTSA2014-0123-0017.
---------------------------------------------------------------------------
In addition, the Alliance explained that tether anchorages cannot
be in the seatback if the seatback plane is located anterior \83\ to
the proposed line in figure 3 of the proposed regulatory text in the
NPRM. To prevent misinterpretation, the Alliance recommended removing
the line from figure 3 in the proposed regulatory text in the NPRM or
amending the requirement to call out this line as a line that
represents the vehicle specific seatback surface within the prescribed
zone, for the seatback profile similar to the callout for the vehicle
floor pan.
---------------------------------------------------------------------------
\83\ The Alliance's illustrations can be found on pages 9 of
Docket No. NHTSA2014-0123-0027.
---------------------------------------------------------------------------
[[Page 1305]]
Agency Response
Comments expressing concerns over how the NPRM proposed to define
the rearmost point of the bottom of the seat to locate the plane
setting the limit of the allowable zone have merit. Therefore,
following careful consideration and evaluation, this final rule adopts
requirements to specify the allowable tether anchorage zone under the
seat using a vertical plane 120 mm rear of the H-Point to define the
allowable limit.
Commenters presented several scenarios in which defining the
rearmost point of the bottom of the seat was not possible, as the
proposed requirement did not provide sufficient details on how to
precisely define it. Commenters also stated that some existing easily
accessible tether anchorages near the back of but slightly under the
seat may not be compliant with the proposed tether anchorage zone.
These anchorages are considered easily accessible because the seats do
not require folding to access the anchorages and the anchorages can be
easily identified since they have the proposed markings.
In acknowledgment of these concerns the Agency did a series of
installations and measurements to evaluate whether the vehicles with
existing tether anchorages near the back but slightly under the seat
are easy to use, and to determine whether the zone under the seat
suggested by Ford is appropriate to define the allowable tether zone
under the seat.\84\ NHTSA selected three vehicles (2015 Toyota Sienna,
2018 Freightliner Sprinter, and 2020 Ford Transit) with tethers located
low on the seatback (similar to the ones commenters stated were easily
accessible locations) to evaluate whether they were easily accessed
when installing a CRS, whether the tether anchorage location would fail
to be located within the NPRM's proposed allowable tether anchorage
zone, and whether it would be within the Ford-proposed allowable tether
anchorage zone (defined by a vertical plane 120 mm rearward of the SgRP
as the forward limit of the allowable tether anchorage zone).
---------------------------------------------------------------------------
\84\ Evaluation of FMVSS No. 225 Tether Anchor Zones Under the
Seat. May 2022. Kedryn Wietholter, National Highway Traffic Safety
Administration. Evaluation summary will be docketed along with this
final rule.
---------------------------------------------------------------------------
In conducting the evaluation, NHTSA installed the Evenflo Triumph
and the Britax Advocate Clicktight in the three selected vehicles to
determine whether the tether was easily installed. The trials showed
that the tether anchorages were easy to locate and use for attaching
the CRS tether anchor connectors.
NHTSA defined the allowable tether zones under the seat using both
the NPRM's proposed zone (parallel torso reference line that passed
through the rearmost point of the bottom of the seat) and Ford's
proposed zone (defined with a vertical plane 120 mm rearward of the H-
point) \85\ in the three selected vehicles. These measurements were
performed to verify whether Ford's proposed method for defining the
allowable tether zone under the seat would remove the ambiguities
present in the NPRM's proposed zone, and to evaluate whether the tether
anchorages in the vehicles are located within the NPRM's proposed
allowable zone and/or Ford's proposed zone (but using the H-point
rather than the SgRP suggested by Ford).
---------------------------------------------------------------------------
\85\ NHTSA chose to use the H-point as it can be measured in the
laboratory as opposed to the SgRP, which is a manufacturer-defined
point. Both points are very similar.
---------------------------------------------------------------------------
The evaluations confirmed that defining the tether anchorage zone
with the vertical line 120 mm behind the H-point removed the
ambiguities contained in the NPRM's proposed method. The evaluations
showed that the tether anchorages of all three vehicle seats were easy
to access and use for installing child restraints. However, these
tether anchorages would not meet the allowable tether anchorage zone
proposed in the NPRM, while they would pass using the 120 mm behind the
H-point measurement method. This result indicates that an allowable
tether anchorage zone determined as a plane 120 mm rearward of the H-
point better reflects ease of access and use of the tether anchorages
than the NPRM's proposed allowable zone.
Table 1--Summary of Tether Anchorage Location With Respect to the NPRM's Proposed Allowable Tether Anchorage Zone and That Determined as a Plane 120 mm
Behind the H-Point
--------------------------------------------------------------------------------------------------------------------------------------------------------
Final rule zone
Year Manufacturer Model Seat position Current zone NPRM zone (120 mm behind H-
point)
--------------------------------------------------------------------------------------------------------------------------------------------------------
2015............................ Toyota............ Sienna............ 2nd Row Driver Pass.............. Fail.............. Pass.
Outboard.
2018............................ Freightliner...... Sprinter.......... 2nd Row Passenger Pass.............. Fail.............. Pass.
Outboard.
2020............................ Ford.............. Transit........... 2nd Row Passenger Pass.............. Fail.............. Pass.
Outboard.
--------------------------------------------------------------------------------------------------------------------------------------------------------
The NPRM's proposed requirement sought to eliminate tether
anchorages located deep under the seat where folding the seat is
necessary to reach it. NHTSA believes the limit on the tether anchorage
location under the seat defined by a vertical plane 120 mm rear of the
H-Point meets this intent. NHTSA also concludes that using a vertical
plane 120 mm rearward of the H-point is easily defined, removes
ambiguities commenters noted in the NPRM's proposed tether anchorage
zone, and better reflects the accessibility and usability of the tether
anchorages. Therefore, the agency is adopting requirements to specify
the allowable tether anchorage zone under the seat using a vertical
plane 120 mm rear of the H-Point to define the allowable limit. This
requirement will prevent tether anchorages from being located deep
under the seat where they are difficult to access, addressing comments
received.
b. Tightening the Tether
NHTSA proposed requirements to make it easier for a consumer to
attach a child restraint tether hook to a tether anchorage and tighten
the tether strap. Currently, FMVSS No. 225 specifies that tether
anchorages must be located within the shaded zone shown in figures 3 to
7 of the standard for the DSP
[[Page 1306]]
in which the anchorage is installed.\86\ NHTSA proposed to amend FMVSS
No. 225 to require that tether anchorages have clearance space for
tightening the strap.
---------------------------------------------------------------------------
\86\ The standard specifies a reference point ``W'' that is 50
mm (1.9 in) below and 50 mm (1.9 in) rearward of the shoulder
reference point (R-point), and a reference point ``V'' that is 350
mm (13.7 in) vertically above and 175 mm (6.8 in) horizontally back
from the H-point. The standard also specifies a strap wrap-around
length of 200 mm (7.8 in) from the W-point and a strap wrap-around
length of 250 mm (9.8 in) from the V-point (see figure 4 of FMVSS
No. 225). Tether anchorages may be located only within the zone that
is generated using both reference points and their associated strap
wrap-around lengths to ensure there is sufficient distance for a
tether strap and hook to be attached to the anchorage.
---------------------------------------------------------------------------
The NPRM proposed to require a 165 mm (6.5 in) minimum distance
from each tether anchorage to a seat-based reference point for each
designated seating position (DSP) with a tether anchorage. In 2012 the
LATCH Usability study \87\ found that, under the current FMVSS No. 225,
tether anchorages can be located too close to the head restraint, on
top of the seatback, or the tether attachment point on a CRS, resulting
in insufficient clearance to tighten the CRS tether strap. The study
reviewed the tether hardware assembly on 21 child restraint systems
made by 11 different CRS manufacturers.\88\ The review found the tether
hardware assembly of the 21 child restraints ranged from 102 to 184 mm
(4 to 7.2 in) in length, with 15 CRSs having tether hardware assembly
lengths between 140 mm (5.5 in) and 165 mm (6.5 in). The study
suggested that having tether anchorages on a package shelf or behind
the seatback at a distance of at least 165 mm (6.5 in) rearward or
below the back of the head restraint or top of the seatback for DSPs
without a head restraint would provide greater clearance for attaching
the tether hook of a CRS and tightening the strap.
---------------------------------------------------------------------------
\87\ Klinich, K.D., Flannagan, C.A., Manary, M.A., and Moore,
J.L. ``LATCH usability in vehicles.'' Link: <a href="http://deepblue.lib.umich.edu/handle/2027.42/90856">http://deepblue.lib.umich.edu/handle/2027.42/90856</a>. The report was
sponsored by IIHS for developing IIHS's rating of the usability of
the child restraint anchorage systems in various vehicles. See IIHS
Status Report: Vol. 47 No. 3, April 12, 2012. <a href="http://www.iihs.org/sr/default.aspx">http://www.iihs.org/sr/default.aspx</a>.
\88\ This hardware consists of the tether hook and hardware to
tighten and loosen the tether strap.
---------------------------------------------------------------------------
In drafting the NPRM NHTSA reviewed the LATCH usability study and
tentatively determined that specifying a minimum 165 mm (6.5 in)
distance from the tether anchorage to a defined reference point on the
vehicle seat would improve tether anchorages' ease-of-use. The NPRM
explained that this clearance would allow for the tightening of tether
straps in most vehicles without interference from other structures,
such as the head restraint.
The NPRM proposed that the reference point on the vehicle seat,
which NHTSA designated as ``SB,'' be defined as the intersection of the
plane parallel to the torso line reference plane (defined in figure 3
of FMVSS No. 225) that passes through the rearmost point of the seat
and the wrap-around line from the ``V-point'' to the tether
anchorage.\89\ The agency noted that both the V- and W-point could have
been used for determining the vehicle seat reference point SB. NHTSA
selected the V-point to define the reference point because it would
encompass both low mounted and high-mounted tether straps.
---------------------------------------------------------------------------
\89\ The rearmost point of the seat includes the head restraint
if one is present. The V-point represents a low-mounted tether strap
on a CRS and the W-point represents a high-mounted tether strap on a
CRS.
---------------------------------------------------------------------------
1. Tether Anchorage Location--165 mm to a Reference Point
Comments on 165 mm Distance to Reference Point
In response to the NPRM many vehicle manufacturers stated that
requiring manufactures to move tether anchorages to locations meeting
the 165 mm (6.5 in) specification is impractical within current styling
because substantial vehicle components currently occupy the locations.
The Alliance stated that the relocation of a single component has
implications for other design considerations including, but not limited
to, wiring harnesses, body in white attachments and reinforcements,
electromagnetic interference, and radio-frequency interference re-
qualification. FCA stated that moving the tether anchorages rearward
would force a complete redesign of the package shelf, including re-
packaging of the existing package shelf components as well as moving
the reinforcements. FCA said that if speakers or modules must be
relocated to the door or the trunk changes to these components would
also be necessary, including side impact countermeasures, door
electrical wire harnesses, and interior trim modifications. The
Alliance added that many passenger cars with tether anchorages located
in the package shelf behind the seat will not meet the proposed 165 mm
minimum wrap around distance,\90\ even though the anchorages are easy
to use.
---------------------------------------------------------------------------
\90\ The term wrap around distance is a distance measurement
made using a flexible tape measure. One end of the tape is held at a
defined point, the tape is wrapped around desired structures, and
held taut at a second defined point.
---------------------------------------------------------------------------
Many vehicle manufacturers, the Alliance, and Global stated that
tether anchorage distance and CRS hardware incompatibility should be
addressed in FMVSS No. 213 by limiting the size of the tether hook and
other CRS attachment hardware.\91\ Some vehicle manufacturers and the
Alliance provided data on the sizes of tether hooks and hardware in
stating that the lack of uniformity in CRS attachment hardware and its
mounting location on the CRS point to the actual source of the
compatibility issue, rather than the vehicle ``swing zone'' behind the
seatback or head restraint. Hyundai stated that tight installations can
be achieved even with vehicles that have less than the proposed 165 mm
(6.5 inches) distance, with a CRS tether hardware and strap measuring
170 mm (6.7 inches).
---------------------------------------------------------------------------
\91\ The NPRM proposed to limit the tether hook and hardware to
165 mm (6.5 in).
---------------------------------------------------------------------------
The Alliance and Toyota identified potential problems with applying
the proposed procedure to certain vehicles regarding the definition of
the point SB. They presented a case for some head restraints where the
torso reference plane may not intersect the strap wrap around line.
Therefore, for this type of head restraint, the reference point SB does
not exist. The Alliance and Toyota also presented a case in which the
reference point SB cannot be defined when the seatback angle is larger
than the torso angle.
Toyota requested that NHTSA develop a repeatable and feasible
requirement regarding the distance from the tether anchorage to the
DSP. Toyota suggested that because the existence of reference point SB
is dependent on the rearmost point of the seat, which can vary
dramatically based on seat design, one potential method to solve this
issue would be to develop a new tool to measure the distance of 165 mm
from the tether anchorage instead of using the concept of reference
point SB.
Several commenters also suggested an alternative way of defining a
clearance zone. FCA recommended a general redefinition of the reference
point SB without providing a suggested definition. The Alliance opined
that the proposed minimum wraparound distance, measured from point SB,
is unnecessarily stringent and does not take current CRS installation
practices into account. The Alliance and Honda recommended that a point
farther forward in the vehicle DSP, representing a tether attachment
point on a child restraint, would provide a more practicable reference
point for this measurement.
Britax stated that mandating a minimal vehicle interior distance
should facilitate better tether
[[Page 1307]]
installation, particularly in sedan vehicles with rear windows close to
rear seatbacks. Britax anecdotally noted it has experienced situations
where the distance between the vehicle seat and tether anchorage would
not permit proper tether attachment and tightening. UMTRI supported the
implementation of a 165-mm clearance around the tether anchorage in
vehicles and the regulation of a maximum adjusted length of the tether
attachment hardware to 165 mm to improve compatibility. UMTRI noted
that these recommendations were based on usability testing of CRS with
a single strap tether.
Post NPRM Research
UMTRI Research
After carefully reviewing comments that raised concerns over the
proposed 165 mm tether anchorage clearance criterion, the agency
determined that it was appropriate to task UMTRI with conducting a
study \92\ to: (1) define an alternate reference point to the proposed
SB point that would be more practical, (2) ensure that the requirements
do not interfere with Australian Design Rule (ADR) 34/2,\93\ (3)
estimate the number of vehicles that may need modification to meet
clearance criteria based on the proposed and alternative reference
points, and (4) evaluate alternative ways of ensuring tether tightness.
---------------------------------------------------------------------------
\92\ Klinich, K.D., Boyle, K., Orton, N.R., Manary, M.A., &
Ebert, S. (2016, January). Investigation of clearance criterion
between tether anchor and head restraint. Ann Arbor: University of
Michigan Transportation Research Institute. Report will be docketed
alongside this final rule.
\93\ ADR 34 Link: <a href="https://ablis.business.gov.au/service/vic/australian-design-rule-adr-34-child-restraint-anchorages-and-child-restraint-anchor-fittings/24383">https://ablis.business.gov.au/service/vic/australian-design-rule-adr-34-child-restraint-anchorages-and-child-restraint-anchor-fittings/24383</a>. This standard specifies a clearance
around the tether anchorage to enable access and attachment of the
tether hook to the anchorage.
---------------------------------------------------------------------------
In carrying out its study UMTRI used two data sets to estimate the
proportion of vehicles that would meet the proposed 165-mm clearance
criteria. First, UMTRI surveyed 60 top selling 2012-2013 MY vehicles to
collect data on each vehicle's tether anchorage location, head
restraint characteristics, and tether routing path. UMTRI used a rigid
165-mm gauge with tether hook to evaluate whether the tether anchorage
location met the proposed criteria. This data set showed that 21 of the
surveyed vehicles had tether anchorages on the rear package shelf.
Eighteen of these vehicles were sedans and three were pickup trucks. Of
the sedans, only one met the proposed criteria. For the 17 sedans that
did not meet the NPRM's proposed criteria, routing the tether over the
head restraint improved access to the tether hardware.
UMTRI surveyed photos of the 21 vehicles with a tether in a package
shelf to evaluate potential barriers in moving the tether anchorages.
About half of the vehicles had no visible barriers at outboard seating
positions, two vehicles had potential for interference from rear window
glazing during installation, and the remaining vehicles had speakers in
the way. The center seating position in 5 vehicles had rear defroster
structures that may be in the way of relocation.
The second data set used a survey of 98 top selling 2010-2011 MY
vehicles. The tether anchorage location was measured for these vehicles
via wraparound distance relative to an estimated shoulder reference
point. These surveys collected photos that helped identify structures
that would hinder any tether anchorage relocation if the 165 mm
criterion was not met. Data from the 98 vehicle-dataset showed that 44
percent of vehicles with the tether anchorage on the seatback would
meet the 165 mm criterion. Of the 35 vehicles with the tether
anchorages located in the package shelf of the outboard seating
position, 24 percent would not meet the 165 mm criterion, but could
improve usability if the tether was routed over the head restraint.
UMTRI then developed an alternate reference zone using established
reference points such as the H-point (hip point) and the R-point
(shoulder point) using 21 vehicles (MY2010-2014) scanned by UMTRI
during previous projects.\94\ A circle with a 325 millimeter radius
centered on the R-point and truncated 230 mm below its center was used
to create the limits of the allowed tether anchorage zone.
---------------------------------------------------------------------------
\94\ See Table 1 in the report titled ``Investigation of
clearance criterion between tether anchor and head restraint'' by
UMTRI. Report will be docketed along this final rule.
---------------------------------------------------------------------------
UMTRI evaluated 11 SUVs and trucks in the scanned vehicle dataset
\95\ that had an upper seatback tether anchorage location. To avoid
conflicts with the IIHS usability rating criteria \96\ the circle was
truncated at 230 mm below the R-point. Doing so allowed for the tether
anchorage to be located far enough to ensure tightness while not
conflicting with IIHS usability rating criteria.
---------------------------------------------------------------------------
\95\ The other 10 vehicles were sedans.
\96\ IIHS LATCH usability rating considers tether anchorages
located in the top 85 percent of the seat back as ``good.'' The IIHS
LATCH Usability Rating Guidelines can be found here: <a href="http://www.iihs.org/media/8f828313-d122-4d27-a3b0-f2b8ec60065d/wOdYVA/Ratings/Protocols/current/LATCH_rating_guidelines.pdf">www.iihs.org/media/8f828313-d122-4d27-a3b0-f2b8ec60065d/wOdYVA/Ratings/Protocols/current/LATCH_rating_guidelines.pdf</a> (last accessed 4-16-2024).
---------------------------------------------------------------------------
UMTRI evaluated the proposed and alternative tether anchorage
clearance criteria against 20 of the 21 \97\ scanned vehicles (MY2010-
2014) to determine whether vehicles met the proposed distance criteria
and quantify the distance a tether anchorage would have to be relocated
if that vehicle did not meet the proposed or alternative criteria.
Results were mixed.\98\ Eleven models met both criteria. Four failed
both criteria but using the alternative criterion the tether anchorage
relocation distance was shorter than for the 165 mm clearance
criterion. Two passed the alternative criterion but failed the 165 mm
criterion. Two vehicles with tether anchorages in the upper seatback
(and not the package shelf) passed the 165 mm criterion but failed the
alternative criterion. For these two vehicles, tightening the tether
was difficult for installing some child restraints. The tether
anchorages for these two vehicles would need to be moved 1-2 mm lower
to meet the 325 mm truncated sphere zone, which would also permit
tightening the tether.
---------------------------------------------------------------------------
\97\ The Ford F150 was not evaluated, as pickup trucks have
different geometry.
\98\ See Table 1 in UMTRI's report for detailed results.
Klinich, K.D., Boyle, K., Orton, N.R., Manary, M.A., & Ebert, S.
(2016, January). Investigation of clearance criterion between tether
anchor and head restraint (Report No. UMTRI-2016-4). Ann Arbor:
University of Michigan Transportation Research Institute. Report
will be docketed along with this final rule.
---------------------------------------------------------------------------
UMTRI also performed in-vehicle evaluations for both tether
anchorage clearance criteria on 10 vehicles (MY 2004-2014).\99\ For
this set of vehicles UMTRI found that three vehicles failed both
criteria, while seven met both criteria. Of the three vehicles that
failed both criteria, the distance to move the tether anchorages to
meet the alternative criterion was shorter than that for meeting the
proposed criterion in two vehicles.
---------------------------------------------------------------------------
\99\ See Table 2 in UMTRI's report for detailed results.
Klinich, K.D., Boyle, K., Orton, N.R., Manary, M.A., & Ebert, S.
(2016, January). Investigation of clearance criterion between tether
anchor and head restraint (Report No. UMTRI-2016-4). Ann Arbor:
University of Michigan Transportation Research Institute. Report
will be docketed along with this final rule.
---------------------------------------------------------------------------
In its review of the two vehicle surveys UMTRI found that about
one-third of vehicles had tether anchorages located on the package
shelf and that the majority did not meet the 165-mm criteria if the
tether strap was specified for routing under the head restraint.
However, UMTRI found that in most of these vehicles routing the tether
strap over the head restraint provided good access to the tether
adjuster hardware.
VRTC Research
Following review of the UMTRI study, VRTC evaluated the alternative
criterion (zone based on a 325 mm circle centered on the R-point), the
proposed 165 mm clearance distance, and the
[[Page 1308]]
lengths of CRS tether hardware.\100\ VRTC measured six vehicles with
various tether anchorage locations in the rear driver side position and
rear center position.
---------------------------------------------------------------------------
\100\ Wietholter, K., & Smith, J. (2019, November). Evaluation
of tether anchor zones for FMVSS No. 225 (Report No. DOT HS 812
842). Washington, DC: National Highway Traffic Safety
Administration. Report will be docketed along with this final rule.
---------------------------------------------------------------------------
Tether Anchorage Measurements
The VRTC Tether Anchorage Measurement results were similar to those
found by UMTRI (see Table 2). The six vehicles' seating positions with
package shelf tether anchorages failed the proposed 165 mm distance.
Only two of those six tether anchorages failed the alternative
criterion. Of the two vehicles that failed both criteria, the needed
relocation distance of the tether anchorage to meet the criteria was
smaller for the alternative criterion than the proposed criterion. All
seating positions with the tether anchorage on the seatback or roof
passed both criteria.
Table 2--VRTC Tether Anchorage Vehicle Survey Results
--------------------------------------------------------------------------------------------------------------------------------------------------------
Vehicle Tether location
------------------------------------------------------------------------------------------------------------------------ 325 mm zone 165 mm tether
Rear driver Rear center (mm) distance (mm)
Year Make Model position (RDP) position (RCP)
--------------------------------------------------------------------------------------------------------------------------------------------------------
2010 Ford Taurus............................................................. Package Shelf...... ................... 384 149
Package Shelf...... 436 141
--------------------------------------------------------------------------------------------------------------------------------------------------------
2011 Cadillac CTS............................................................ Package Shelf...... ................... 294 68
Package Shelf...... 409 74
--------------------------------------------------------------------------------------------------------------------------------------------------------
2016 Toyota Sienna........................................................... Seatback........... ................... 742 757
N/A................ N/A N/A
--------------------------------------------------------------------------------------------------------------------------------------------------------
2011 Hyundai Sonata.......................................................... Package Shelf...... ................... 308 75
Package Shelf...... 365 65
--------------------------------------------------------------------------------------------------------------------------------------------------------
2016 Chevrolet Tahoe......................................................... Seatback........... ................... 625 657
Seat Back.......... 628 637
--------------------------------------------------------------------------------------------------------------------------------------------------------
2016 Nissan Rogue............................................................ Seatback........... ................... 433 469
Roof............... 630 460
--------------------------------------------------------------------------------------------------------------------------------------------------------
VRTC found one of the six vehicles' tether anchorages was off-
center for its designated seating position. VRTC used a FARO arm \101\
to plot the desired points into a 2D circle diagram. Due to the offset,
measurements for that tether anchorage do not correctly capture the
depth distance. Therefore, VRTC used a 325 mm sphere (truncated at the
bottom) instead of a two-dimensional circle to define the 325 mm zone
(see figure 4).
---------------------------------------------------------------------------
\101\ A FARO arm is a portable coordinate measuring machine that
measures the location of a probe in a 3D space.
[GRAPHIC] [TIFF OMITTED] TR07JA25.029
CRS Hardware Measurements
VRTC also measured the tether hardware length of twenty CRSs. The
longest tether strap hardware was 190 mm. The shortest was 83 mm.
Sixteen of the twenty tether hardware were less than 165 mm in length.
CRS Installation on Vehicles
VRTC completed CRS installations to verify that a vehicle with a
165-mm tether anchorage distance measurement would allow for proper
installation of a CRS with a tether hardware length of 165 mm. The CRS
selected was an Evenflo Triumph with a tether hardware length of 164
mm. Two vehicles with short distances (close to the 165 mm proposed
minimum distance) to the tether anchorage were selected for this
portion of the study. The 2010 Ford Taurus (RDP), which had a 149-mm
[[Page 1309]]
tether anchorage distance measurement, was closer to 165 mm than the
other selected vehicle. The 2011 Cadillac CTS (RCP) had one of the
smaller tether anchorage distance measurements of 74 mm and an odd seat
shape. Both the 2010 Ford Taurus (RDP) and 2011 Cadillac CTS (RCP)
positions passed the UMTRI alternative criterion based on the 325-
millimeter circle centered on the R-point.
Because the 2010 Ford Taurus (RDP) had a tether anchorage distance
measurement from the proposed SB point of less than 165 mm, the study
anticipated that the tightening of the tether would be difficult.
However, the vehicle owner's manual included instructions to install
the CRS using the tether attachment by routing it under the head
restraint. Since the head restraint was adjustable, no difficulties
were experienced when tightening the tether. This result suggests that
the tether anchorage distance measurement, defined as the distance from
the tether anchorage to the rearmost point on the seat (SB point), does
not account for the ease of installation when the head restraint is
raised or removed for CRS installation.
Further, since the tether anchorage distance from the SB point for
the 2011 Cadillac CTS (RCP) was only 74 mm (significantly lower than
the proposed 165 mm), NHTSA expected that the tether would be difficult
to tighten when installing a CRS in this seating position. However,
installation was not difficult because of the lack of head restraint.
Specifically, the seatback cushion in the Cadillac was thick, which
allowed enough space between the tether anchorage and the CRS for the
tightening of the hardware. For the 2011 Cadillac CTS (RDP), the
vehicle owner's manual specified that the CRS tether attachment should
be routed over the fixed head restraint, which permitted easy
tightening of the tether attachment. If a vehicle with similar spacing
had an adjustable head restraint and specified routing under the head
restraint in the vehicle owner's manual, it would have been difficult
to tighten the tether attachment because the tether attachment hardware
would be underneath the head restraint. This finding indicates that
ease of installation can be improved with vehicle owner's manual
instructions and not just measurement requirements.
Agency Response
After carefully considering comments received and reviewing the
results of the UMTRI and VRTC studies, this final rule is implementing
a 325 mm radius sphere zone (from R point, with truncation) instead of
the NPRM's proposed 165-mm distance from the tether anchorage to the
back of the seatback. The decision to adopt the alternative 325 mm zone
resolves noted issues in defining the SB point for the 165-mm distance,
because the R-point, already defined in the standard, is used in the
alternative 325 mm radius sphere zone to define the center of the
sphere. Therefore, NHTSA will adopt a 325 mm radius sphere zone (from
R-point, with truncation) to define the allowable area for the tether
anchorages.
Some commenters, including Honda, Alliance, Ford, and FCA,
expressed concern for the expensive tooling costs needed to relocate
the tether anchorages. However, the modified requirements adopted by
this final rule will minimize or eliminate the number of vehicles that
need tooling changes to relocate the tether anchorages, greatly
reducing any projected tooling costs.
NHTSA acknowledges Honda's suggestion that the required minimum
distance of the tether anchorage should be from a point simulating the
attachment of the tether strap on the CRS to the tether anchorage,
rather than the SB point. However, the current specifications of the
tether anchorage location in FMVSS No. 225 are with respect to the W-
point, which is approximately the tether strap attachment point on the
CRS. Additionally, this final rule's requirements specify a minimum
distance of the tether anchorage with respect to the R-point, which was
found to be sufficient for correctly installing and tightening the
tether of CRSs. This final rule's adopted approach achieves the goal of
improving usability in a practicable manner without imposing design
restrictions and undue cost and redesign.
Finally, NHTSA is providing a longer lead time (discussed in detail
below) to minimize any costly design changes borne by manufacturers to
move tether anchorage locations during the mid-lifecycle of their
vehicles.
Comments on Backlight Interference
Several commenters, including FCA, the Alliance, and Hyundai,
raised concerns that moving the tether anchorage rearward will likely
interfere with the backlight during child restraint tether hook
attachment and detachment. FCA noted that the slope of the back glass
may need to be changed to alleviate the interference condition. FCA
further stated that all of its current tether anchorages are harmonized
worldwide and that, if NHTSA mandates relocating the tether anchorage
rearward, its vehicles may no longer meet the requirements of
ADR34,\102\ which governs child restraint anchorages for vehicles sold
in Australia. FCA stated that ADR 34.6 requires accessibility to engage
an attaching clip and a clearance zone around the tether anchorage. FCA
stated that, in the worst-case event, two designs for the package shelf
might be necessary, which would increase the overall vehicle cost in
all markets. The Alliance stated that the proposed requirement's forced
relocation of tether anchorages rearward in the vehicle would result in
less hand clearance to the vehicle backlight for attaching and
detaching the tether hook.
---------------------------------------------------------------------------
\102\ Australian Design Rule 34. The stated function of this
Australian Design Rule is to specify requirements for ``Child
Restraint Anchorages' and `Child Restraint Anchor Fittings' which
provide for the connection of standard `Attaching Clips' so that
`Child Restraints' may be adequately secured to the vehicle. It
specifies a standard package of fitting hardware and accessibility
requirements to facilitate correct installation and
interchangeability of 'Child Restraints'. <a href="http://www.infrastructure.gov">www.infrastructure.gov</a>.au/
infrastructure-transport-vehicles/vehicles/vehicle-design-
regulation/australian-design-rules/third-edition. Last accessed
November 4, 2024.
---------------------------------------------------------------------------
Agency Response
With this final rule's adoption of the aforementioned changes in
determining the allowable tether anchorage zone, any cases where the
tether anchorage is pushed back towards the rear window, causing
potential conflict with the ADR, will be minimized or eliminated.
However, UMTRI's evaluations of the updated measurement showed a small
portion of vehicles would still experience conflict based on the
requirements of this final rule, so some vehicle designs would have to
find alternative locations or design to meet both ADR 34 requirements
and FMVSS No. 225 requirements. To the extent doing so is required, the
extended lead time and phase-in period provided by this final rule
should help to alleviate cost and design burdens to manufacturers.
Comments on Head Restraints and Routing of Tether
The Alliance suggested that the tether anchorage location
requirements relative to the back of the seat or head restraint should
not apply to vehicle seating positions (1) without a head restraint,
(2) with a head restraint that is removed for child restraint
installation, or (3) when the vehicle manufacturer specifies that the
tether strap is to be routed over or around the head restraint.
Similarly, Global commented that the tether anchorage location
requirements should not apply to seats having adjustable or removable
[[Page 1310]]
head restraints, since such head restraints can be adjusted or removed
to allow sufficient space for tether adjustment. Global agreed that the
distance criterion might be applied to certain seats having a fixed
head restraint, where there is no space between the head restraint and
the seat top to enable tightening of the tether strap.
Agency Response
Following careful consideration, this final rule requires vehicles
with adjustable/removable head restraints and no head restraints to
locate the tether anchorages beyond the 325 mm truncated sphere from
the R point to ensure tethers can be easily tightened. The agency
disagrees with the Alliance's recommendation that the tether anchorage
location requirement behind the seat should not apply to DSPs with no
head restraints and removable head restraints. Vehicles in this
category could run the risk of having the tether anchorage too close to
the CRS, preventing a tight tether installation. While the tether could
be routed over the adjustable/removable head restraint, thereby
increasing the wraparound distance to the tether anchorage and removing
interferences for tightening the tether strap, most manufacturer
instructions specify routing the tether strap under the adjustable/
removable head restraint. Routing the tether under the head restraint
provides the shortest path from the tether anchorage to the CRS, which
may have some benefits during a crash (less webbing length results in
less stretch). Routing the tether under the head restraint may also
offer improved CRS performance in far side impact scenarios as tether
routings over the head restraint sometimes slip to the side of the head
restraint, allowing for more side excursion. In addition, because some
head restraints that protrude or tilt to the front at times interfere
with the installation of the CRS, it is typically advised to remove or
move the head restraint to a higher position to eliminate this
interference. Because adjustable/removable head restraints are likely
to be used with a tether routed under the head restraint (for
adjustable head restraints), it is important to have the tether
anchorage beyond the 325 mm truncated sphere from the R point to ensure
tethers can be easily tightened.
In contrast with the Alliance's recommendation, Global suggested
that the requirement for the tether anchorage location behind the seat
should only apply to DSPs with fixed head restraints. We disagree. As
fixed head restraint seating positions do not have any elements that
interfere with the installation and tightening of the tether, the
agency believes these seating positions should be excluded from the
tether anchorage location requirements to ensure there is sufficient
space to tighten the tether. Additionally, seating positions with fixed
head restraints where the tethers are routed over the restraints
increase the wraparound distance from the CRS to the tether anchorages,
so they are less likely to prevent tightening of the tether due to
limited distance. Finally, there is no interference of the head
restraint to route and tighten the tether for seats with fixed head
restraints. For these reasons, this final rule excludes DSPs with fixed
head restraints from the tether anchorage location requirements.
Comments on Tether Anchorage Location and Pass-Through Door
The Alliance expressed concerns with relocating the center tether
anchorage as proposed in the NPRM in relation to a specific design
featuring a tether anchorage installed above a luggage compartment
pass-through door.\103\ The Alliance stated that the proposed minimum
wraparound distance would necessitate a tether anchorage position lower
on the seatback. The Alliance explained that to accommodate this
revised tether anchor position, the size of the pass-through door/
opening to the luggage compartment would need to be smaller, thereby
significantly limiting its usefulness. The Alliance stated it is not
practicable to locate the tether anchorage on the pass-through door
because the door lacks the structural strength to meet FMVSS No. 225's
tether anchorage strength requirements. The Alliance recommended that
the center seating position should thus be exempted from the minimum
tether anchorage distance requirement relative to the SB point.
---------------------------------------------------------------------------
\103\ Shown in figure 16 of the Alliance's submitted comments.
Link: <a href="http://www.regulations.gov/comment/">www.regulations.gov/comment/</a> NHTSA-2014-0123-0027.
---------------------------------------------------------------------------
Agency Response
The modified requirements adopted by this final rule will minimize
or eliminate the tooling costs that would be necessary to relocate the
tether anchorages, and will minimize or eliminate cases where the
tether anchorage location could interfere with the position of a pass-
through on a center seat (if the tether anchorage cannot be located
elsewhere). If a tether anchorage can't be located towards the top of
the seat within the new requirements because of a pass-through opening,
the tether anchorage could instead be located lower in the seat where a
tether strap would go over the pass-through opening area. This scenario
would not interfere with the function of the pass-through door because
it would not be used when a CRS is installed in the center seating
position. As such, the agency is declining to adopt the proposed
exemption.
Comments on the Need for Vehicle Manual Information
SRN stated that head restraints present a significant impediment to
tethering the CRS in many vehicles and recommended that FMVSS No. 225
require vehicle manuals to provide specific instruction for the proper
routing of the tether vis a vis the head restraint, along with clear
guidance for how to adjust the head restraint to achieve proper routing
when necessary. SRN explained that because tethers come in two styles
that affect routing (two-point and three-point), instructions should be
required to address these differences. SRN also stated that
instructions calling for the removal of the head restraint should
clarify whether the head restraint can be reattached once the tether is
attached, or, if not, where the head restraint should be safely stored.
SRN stated that some vehicle owner's manuals have improved these types
of instructions over the years, but that this improvement is far from
consistent. SRN also stated that in some cases, cargo covers, dog
gates, and other accessories supplied by the vehicle manufacturer
impede the route of a tether to the tether anchorage. Based on these
issues, SRN suggested that the manufacturer be required to provide
clear tether routing instructions in the vehicle's manual.
Agency Response
The agency is declining SRN's suggestion to require tether routing
instructions in vehicle manuals, as it falls outside scope of the
proposed requirements in the NPRM and this rulemaking. NHTSA may
consider the addition of instructions for tether routing in vehicle
owners' manuals at a later date.
Comments on the Length of the Minimum Distance to the Tether Anchorage
and Maximum Length of the Tether Hardware
SRN supported efforts to match up the distance from the child
restraint to the tether anchorage and a maximum length of the tether
hardware (the hook + adjuster). However, SRN expressed concern that by
specifying 6.5 inches as
[[Page 1311]]
both the minimum for the distance from the child restraint to the
vehicle's tether anchorage and a maximum for the very shortest tether
length, it will continue to be difficult to properly tighten the tether
when both the CRS and vehicle meet (but do not exceed) the standard.
SRN stated that the minimum distance to the tether anchorage should be
at least a half inch (or more) greater than the maximum-allowed fixed
length of the tether anchorage for the solution to be effective in all
situations (for example, the shortest length for the tether hook and
adjuster could be a maximum of 6 inches and the tether anchorage
distance no less than 6.5 inches).
Agency Response
SRN commented that having the same 165 mm distance as the
requirement to both the tether anchorage distance and the tether
hardware length does not ensure proper tightening of the tether,
commenting that the minimum distance of the tether anchorage needs to
be at least a half inch (or more) greater than the maximum allowed
fixed length of the tether hardware for the solution to be effective.
As the final rule requirements for tether anchorage location have been
modified from those proposed in the NPRM, SRN's suggestion no longer
applies to this final rule.
In support of the modifications adopted in this final rule, during
the VRTC CRS hardware survey, only 4 of the 20 CRSs had hardware
exceeding the 165 mm limit. This finding supports NHTSA's decision to
adopt a tether hardware length requirement of 165 mm or less as
proposed, as most CRSs already comply with this length. Any changes
needed to the tether hardware design in CRSs that currently do not meet
this length should not be burdensome, as there are many tether hardware
designs available that meet the requirement. Further, this requirement
will help address the Alliance and FCA's suggestions to promote CRS
uniformity.
Comments on Requiring Tether Anchorages To Be Close to the Proposed 165
mm Requirement
ARCCA commented that NHTSA's assessment of tether anchorage
locations appeared to only consider the tether's effectiveness in
frontal crashes. ARCCA stated that side impact crashes can result in a
similar number of injuries and fatalities as frontal crashes, and that
they should be given equal consideration. ARCCA explained that the
tether is most effective in frontal crashes, and that a tether also
reduces the amount of roll that a forward-facing CRS experiences when
the tether length is sufficiently limited. ARCCA added that its own
sled testing and quasi-static load testing indicate that the longer the
tether, the more the CRS can roll towards the impact during a side
impact, and that an increased CRS roll results in increased lateral
head excursion. ARCCA explained that this increased head excursion
results in increased head impact injuries, the most frequent mechanism
of serious injury. For these reasons, ARCCA recommended that tether
anchorage locations should be limited to the package shelf and the back
of the vehicle seat, and as close to the proposed 165 mm (6.5-inch)
minimum as possible. Alternatively, ARCCA recommended that when the
distance of the tether anchorage exceeds the 165 mm (6.5-inch) minimum,
a tether guide should be provided at the back top of the seatback that
has sufficient strength to maintain the tether within the guide during
side impact crashes.
Agency Response
This final rule will not reduce the allowable tether anchorage zone
to distances close to 165 mm from the SB point as possible, as
suggested by ARCCA, because doing so would greatly reduce the allowable
tether zone in the standard and may not be feasible in some vehicle
designs.
ARCCA's suggested proposal to include a tether guide is not within
the scope of this rulemaking, and will thus not be addressed, as it was
not proposed in the NPRM and NHTSA does not have any data on tether
guides to aid in side impact crashes.
Requests for Clarification
Global requested clarification of the following:
<bullet> Which portion of the routing device will be the reference
position for the 165-mm distance measurement?
<bullet> How much force is to be applied on the strap when making
the measurement?
Agency Response
As the agency is not adopting the 165 mm distance from the SB point
to the tether anchor, these requested clarifications are moot and need
not be addressed, as they do not relate to requirements of this final
rule.
2. Tether Hardware Restrictions
To improve compatibility between vehicles and CRSs, NHTSA proposed
to amend FMVSS No. 213 to require that the tether hardware assembly
(consisting of the tether hook and hardware to tighten and loosen the
tether strap) be no longer than 165 mm (6.5 in). NHTSA proposed this
limit so that all CRS tether straps can be tightened given the minimum
tether anchorage distance from the SB reference point. NHTSA stated
that limiting the length of the tether hardware assembly would not be
overly burdensome for CRS manufacturers, since the assembly consists of
simple parts.
General Comments
The Alliance and FCA opined that the tether anchorage distance and
CRS hardware incompatibility is better addressed through the
introduction of design rules for the attachment hardware in FMVSS No.
213. The Alliance stated that a survey of 16 child restraints
manufactured between 2003 and 2014 found that attachment hardware
lengths varied from 120.6 to 171.4 mm (4.75 to 6.75 inches) in length,
tether hooks alone varied from 60.3 to 63.5 mm (2.375 to 2.5 inches) in
length, and adjuster assemblies varied in both length and circumference
(from 120.6 to 196.8 mm (4.75 to 7.75 inches) in circumference). The
Alliance stated that the lack of uniformity in CRS attachment hardware
and its mounting location on the CRS points to the actual source of the
compatibility issue, rather than the vehicle ``swing zone'' behind the
seatback or head restraint. Similarly, Hyundai presented a 12 CRS
hardware length survey that found a range between 140 to 185 mm (5.5 to
7.3 inches). Hyundai stated that limiting the length of the tether
hardware assembly would not be overly burdensome for CRS manufacturers,
since that assembly consists of simple parts.
Britax recommended against adopting restrictive dimensional
requirements for tether hardware length (165 mm), as it might prevent
advancement in tether technologies, and against requiring child
restraint manufacturers to modify current tether hardware design.
Instead, Britax recommended that child restraint manufacturers simply
provide compatible tether hardware as the vehicle tether anchorage
dimensions are standardized.
Agency Decision
This final rule adopts a tether hardware length requirement of 165
mm or less as proposed by the NPRM. Most CRSs already comply with this
length and changing the tether hardware design in CRSs that currently
do not meet this requirement should not be burdensome, as there are
many tether hardware designs available that can meet the requirement.
Although Britax did not describe how a new tether
[[Page 1312]]
technology would not be able to comply with this requirement, any
hardware design with a longer distance than 165 mm could prevent tight
installations, and therefore, would not comply. Having this requirement
will also address the Alliance and FCA's suggestion to promote CRS
uniformity.
V-Shaped Tethers
Britax stated it has a patented tether technology which
incorporates, in part, a V-shaped tether assembly. Britax stated that
the V-shaped tether assembly would meet the proposed tether hardware
length requirement. In contrast, UMTRI stated that for V-shaped
tethers, the adjustment hardware is typically located a considerable
distance from the tether hook, so these tethers may not be able to
comply with the proposed requirement. UMTRI also stated that has had
had difficulties tightening the V-shaped tether in some Britax CRSs.
Agency Decision
Unlike common tethers that are usually routed directly from the
middle of the CRS back to the tether anchorage, a V-shaped tether is
routed from the two CRS attachments near the side of the CRS back to
the tether anchorage.\104\ A V-shaped tether would most likely have a
longer distance from each of the back/side attachment points to the
tether anchorage and would not have a head restraint interfering during
attachment, as it is routed on either side of the head restraint.
Factors outside the scope of the proposed requirements on tether
anchorage location and tether hardware length may be the cause of
difficulties in tightening V-shaped tether anchorages. However, any
potential solution is out of scope of this rulemaking and will thus not
be addressed by this final rule.
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\104\ See details of attachment to the tether anchorage at
<a href="https://us.britax.com/why-britax/innovation/v-shaped-tether">https://us.britax.com/why-britax/innovation/v-shaped-tether</a>.
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c. Noticing the Tether Anchorages
1. Structures Covering Anchorages
The NPRM proposed to require that a tether anchorage must be in a
location where the anchorage is accessible without the need to remove
carpet or other vehicle components to access the anchorages. However,
the NPRM proposed that a tether anchorage may be covered with a cap,
flap, or cover, provided that the cap, flap, or cover is specifically
designed to be opened, moved aside, or otherwise provide access to the
anchorage. It must also be labeled with the ISO symbol indicating the
presence of the tether anchorage underneath. The NPRM also proposed to
require the anchorage to be accessible without the use of any tools,
including the use of a screwdriver or coin.
Covered Tether Anchorages
Dr. Baer strongly disagreed with the provision allowing for the
covering of tether anchorages with any cap/flap/cover, stating concerns
that parents do not notice these covers, because vehicle manufacturers
do a very good job of making the caps/flaps/covers blend in with their
surroundings. Dr. Baer stated that aesthetics of the vehicle need to
take a back seat to child safety, and that hiding of the CRAS has
directly contributed to the failure of CRAS to reduce misuse rates in
the population as a whole since so many parents never find the
anchorages in their vehicles.
Agency Response
The agency disagrees that tether anchorage covers should not be
allowed. Data from IIHS's study \105\ shows that the package shelf is
the tether anchorage location most widely used in the field. Tether
anchorage covers are most commonly used in package shelf locations and
are usually voluntarily labeled with the ISO tether symbol. Although
IIHS data does not provide details on whether the tether anchorages in
their study had covers or not, data in the IIHS study suggests that it
is not detrimental to have a labeled cover on the tether anchorages.
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\105\ Jessica B. Cicchino, J.B., Jermakian, J.S. ``Vehicle
Characteristics Associated with LATCH Use and Correct Use in Real-
World Child Restraint Installations.'' April 2014.
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Cargo Covers
The Alliance stated that many SUVs, CUVs, and station wagon-type
vehicles are equipped with a luggage compartment cover. The Alliance
stated that some of these cover designs must be removed when access to
the tether anchorages is required, while others are retracted into
their own housing.\106\ The Alliance commented that the compartment
cover removal does not require any special tools and is, in most cases,
conducted with a simple twist, turn, and lift-up movement of the
hardware. The Alliance added that in some hatch-back and coupe style
vehicles, the package shelf may have to be moved/removed temporarily to
facilitate accessing the tether anchorages on the vehicle
seatback.\107\
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\106\ Illustration can be found on page 14 of Alliance comment
submission in Docket No. NHTSA2014-0123-0027. Link:
<a href="http://www.regulations.gov/document/NHTSA-2014-0123-0027">www.regulations.gov/document/NHTSA-2014-0123-0027</a>.
\107\ Illustration can be found on page 13 of Alliance comment
submission in Docket No. NHTSA2014-0123-0027. Link:
<a href="http://www.regulations.gov/document/NHTSA-2014-0123-0027">www.regulations.gov/document/NHTSA-2014-0123-0027</a>.
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The Alliance provided examples of a hatchback equipped with a
lightweight removable security cover hinged near the seatback on one
side and tethered to the rear hatch on the other side. The Alliance
explained that the cover is designed to be easily removed to transport
large cargo when the rear seat is folded flat and that the cover needs
to be temporarily lifted or removed to attach the tether to the tether
anchorage located on the vehicle structure. The Alliance added that
removing the cover is not an impediment to tethering the CRS and the
regulation should not prohibit manufacturers from providing the
security the covers provide. The Alliance stated that because these
compartment covers are easily removable and provide ready access to the
anchorages, they do not qualify as vehicle components as provided under
the proposed provision.
Global requested clarification on whether luggage room boards or
covers that are readily movable to gain access to the tether anchorage
are permitted under the proposal, and whether such covers must be
labeled.
Agency Response
After careful consideration, this final rule allows cargo covers to
be present if they do not need any tools for removal and are marked
with a tether marking for each tether anchorage available (i.e., if
there are three tether anchorages available under the cargo cover,
there should be three tether anchorage markings). As this cargo cover
could be removed or relocated away from the actual tether anchorage,
the anchorage must also be marked.\108\ The agency considered not
allowing the cargo cover feature, but the cargo cover is a component
that consumers would want to use in most cases to hide the cargo
whenever they do not need to access it from the rear seat. Also,
because the cargo cover does not have sufficient structural strength to
locate the tether anchorage on it, it would not be adequate for
installing tether anchorages.
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\108\ Marking requirements are discussed in a later section of
this final rule.
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Tether Anchorages Located Under the Fabric With Slit
SRN expressed concerns about some tether anchorages located on
vehicle seatbacks and hidden behind the seatback fabric. SRN explained
that although a scored slit in the fabric is provided for this design
(and in some cases, a tether anchorage marking may
[[Page 1313]]
even be nearby), it is consistently difficult for vehicle owners to
recognize how to access these type of tether anchorages. SRN explained
it is hard to see the slit in low light (such as in a garage) and
bewildering to owners that they would be required to perform this step.
SRN commented that, because this type of hidden tether anchorage
technically could meet the requirements of the proposal, wording should
be included in the standard that eliminates this design option and
makes exposing the tether anchorage part of the factory assembly
procedures.
Agency Response
In response to SRN's expressed concerns, the proposed requirements
that ``allow a cap, flap or cover that is specifically designed to be
opened, move aside or to otherwise give access to the anchorage'' would
not permit such slit access (unless it stays open by itself) because it
would not expose the tether anchorage without obstruction. However, in
acknowledgement of this concern and to provide greater clarity and
avoid any potential confusion, NHTSA is modifying this final rule's
regulatory text to ``allow a cap, flap or cover that is specifically
designed to be opened, move aside or to otherwise give unobstructed
access to the anchorage'' to more explicitly rule out slit designs.
Tether Anchorages Under Cargo Floor
Dr. Baer and SRN also commented on tether anchorages located below
the level of the cargo floor (e.g., in the Toyota Prius V), explaining
that when the second-row seating is rolled back to the regular
passenger seating position, the seatback abuts the cargo area floor,
and the tether anchorages are completely out of sight and inaccessible.
SRN recommended that NHTSA address the problem of tether anchorages
that are inaccessible in certain seating locations through an amendment
to FMVSS No. 225.
Agency Response
The proposed requirement to have tether anchorages in a location
available without the need to remove carpet or other vehicle components
to access the anchorages (except for caps, flap or covers designed to
provide access to the anchorage) adequately addresses the concerns
raised over anchorages positioned below the level of the cargo
floor.\109\ The agency considers an interfering cargo floor as a
vehicle component that is not providing access to the tether anchorage,
and therefore not meeting the intent of this requirement. However, as
discussed in the previous section, the agency will change the
regulatory text to ``otherwise give unobstructed access to the
anchorage'' to more explicitly rule out slit designs and obstructed
anchorages below the cargo floor.
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\109\ See <a href="http://www.cars.com/articles/2014/02/2014-land-rover-range-rover-sport-top-tether-trouble-/">www.cars.com/articles/2014/02/2014-land-rover-range-rover-sport-top-tether-trouble-/</a>.
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Tether Strap Over Cargo Area
Dr. Baer stated that other tether anchorage locations include the
rear wall of the vehicle, which makes it impossible to put cargo in the
trunk area with a tether strap crossing over the cargo area. Dr. Baer
explained that when forced to decide between using a tether and having
room for cargo, most parents will choose the cargo and leave the car
seat untethered. Therefore, Dr. Baer disagreed with NHTSA's statement
that ``those atypical locations do not appear to pose a safety
problem.'' Dr. Baer added that while in the crash test lab a rear wall
tether anchorage is fine, in the real world it isn't practical and
simply doesn't get used.
Agency Response
Regarding Dr. Baer's comment on not allowing anchorages that
interfere with cargo space, this is out of the scope of this
rulemaking, as NHTSA did not propose any requirements on this topic or
how to evaluate interference with cargo.
2. Elimination of the Option To Use a Tool or Coin To Remove the
Anchorage Cover
The NPRM proposed that a tether anchorage must be in a location
where the anchorage is accessible without the need to remove carpet or
other vehicle components to access the anchorages. NHTSA also proposed
the anchorage must be accessible without the use of any tools,
including the use of a screwdriver or coin. NHTSA clarified that a
tether anchorage may be covered with a cap, flap, or cover, provided
that the cap, flap, or cover is specifically designed to be opened,
moved aside, or otherwise provide access to the anchorage, and it must
also be labeled with the ISO symbol indicting the presence of the
tether anchorage underneath.
Comments
Advocates
[…truncated; see source link]Indexed from Federal Register on January 7, 2025.
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